Develop Bugs

Fastboot does not work but ADB does

Hey guys,
The power button on my phone stopped working this morning (without water damage). I'm preparing the phone to return to Samsung warranty, and in the process of reseting to stock and re-locking the OEM I noted that the phone does not respond to fastboot commands in the bootloader despite this working on the same system a week ago, no change in drivers or anything else. I installed PDAnet, still broken on Win 7 although I can reboot with adb.
I then tried this on OSX, again I can reboot with ADB, but the phone is unresponsive in fastboot.
I have three working hypotheses and I'm hoping someone can help me:
a) in some process of flashing my phone and being an uninformed n00b maybe I flashed something I shouldn't have or used some combination of partial fastboot flashes I shouldn't have. has this happened to anyone else?
b) whatever hardware damage knocked out the power button might have partially knocked out the bootloader
c) I just have really bad luck with driver set up and I just happened to mess up two different computer driver configurations but the phone is fine. to this end, I am setting up another Win 7 system fresh on a virtual drive as I'm typing, though I have little faith it will be different

update: fastboot commands didn't work on the other windows 7 virtual system, although adb reboot bootloader did
freaking a this is annoying.
i have a fully stock ROM and radio, anybody to know how to flash a new recovery image and lock the bootloader without accessing fastboot? Just have to get this ready to go back to Samsung so they can fix their own hardware mess ups.

they are 2 different drivers.

As much as I don't like using/recommending the Galaxy Nexus Toolkit (only because I feel it's better to actually learn everything you're doing), it's the easiest way I've found to get the Fastboot drivers installed.
http://forum.xda-developers.com/showthread.php?t=1392310

Thanks guys for your comments.
I've tried Android SDK drivers, PDANet, Universal Naked Driver, and now the one click toolkit mentioned above, some on three different operating systems (Win 7, Win 8, OSx) on 32 and 64 bit.
The wierdest part is that under device manager, no device shows up when the phone is in fastboot, no is there any noise or any recognition of the device being connected at all. It is completely, 100% silent. (again, ADB works when the phone is booted).
I recognize that this may not be possible, but does anyone know how to flash a recovery image without being in the bootloader mode?

If fastboot isnt working like it should, and you are sure it isnt user error, then take it for warranty.
Sent from my i9250

yeah fastboot + the power button (which was defunk in clockwork mod) are back online again, dunno for how long. agreed seems like a hardware/warranty issue.

Recoveries can be flashed with ROM Manager assuming you have SuperUser permissions, but otherwise you or the toolkit need fastboot working.
Sent from my Galaxy Nexus using xda app-developers app

SOLVED Wug's toolkit has me jammed.

Edit: I had switched to a different (charge-only) cable halfway through and not realized it. Switched back and the phone was recognized again.
Steps:
I unlocked my bootloader with Wug's toolkit.
I installed the zips that it asked me to (that it put on my SD card).
I updated SuperSU
I got a notice to update the SuperSU binary.
SuperSU binary won't install via Play.
Tried to install via TWRP and recovery isn't twrp, seems to be stock recovery (thought I installed it, maybe not)
Now the toolkit won't recognize my device. neither will windows. It gives me the USB noise but won't show the device in the folder list and defaults to USB for Charging. I can change it but it doesn't make it recognizable.
I'm trying ot back out and try again but the toolkit says it finds the device but that it's listed as "offline". When I toggle the USB debugging, it doesn't ask me to fingerprint my computer.
When I try the "soft brick" option to flash from the bootloader, the script reports a failure "data transfer failure (unknown error)", then says "rebooting into bootloader..." and does nothing else BUT my phone's bootloader still says "downloading..." When I reboot, the script throws another failure and says "waiting for device". when I bootload into it again and connect, the script throws more failures.
I've been on this for 4 hours, getting pretty fatigued (through the night on a weekend when family is visiting. yes, I'm an idiot for trying this procedure but the 5 went so smoothly I was optimistic).

try reinstalling the drivers. also the OEM-lock option in the dev-settings may help bringing you back to step one.

I was halfway through installing the drivers when I quit for sleep last night.
I'm using the LG-Mobile-Driver_v3.14.1.exe package, and the installer says it installed successfully, but windows says that MTP and PCI Simple Communications Controller had "No driver found", so the device doesn't show up in my drive list and wugfresh won't detect it.
I've removed all Google, LG, MTP, and Nexus drivers in USBDeview, but can't seem to figure this out.
I was able to get the drivers installed on my wife's system, so I'll open another thread about this if I can't get them to work.

Try using @Heisenberg root instructions if you get back to stock. I've tried multiple times to use the toolkit to no avail. I've had to resort to Heisenberg's root method every time and it just works.
You may wonder why I've rooted multiple times...I was testing with Android Pay and wanted to start clean. Although I was able to use the toolkit to get back to stock easily.

oubravs2b said:
Try using @Heisenberg root instructions if you get back to stock. I've tried multiple times to use the toolkit to no avail. I've had to resort to Heisenberg's root method every time and it just works.
You may wonder why I've rooted multiple times...I was testing with Android Pay and wanted to start clean. Although I was able to use the toolkit to get back to stock easily.
Click to expand...
Click to collapse
so, the reason my computer stopped recognizing the phone was that I switched to a charge-only cable without realizing it. Switched back and the phone recognized fine.
The weird thing is, the charge-only cable worked fine for data xfer on my wife's system.

[H811] ADB Broken after Rooting?

Yesterday I decided to install ClockworkMod. I was running 6.0.0 Marshmallow
I unlocked my bootloader no problem. I decided to root before I flashed the rom. I booted into TWRP using adb, made a nandroid backup, and flashed stock-20a-rooted.zip (I was following this guide). It worked! I used a rootchecker app to ensure I had a good root. Then I went to boot into TWRP to install ClockworkMod. I turned off my phone and did the volume down + power thing, but I got the LG hard factory reset screen. So I decided to use ADB instead and rebooted my phone. However, when I tried to use adb, my device was listed as "unauthorized", and I haven't been able to use adb since! Here's what I tried (but not necessarily in this order):
Using the LG hard factory reset. Nothing changed.
clearing adbkey file on my computer. Nothing changed.
using a different computer with fresh adb and driver install. Nothing changed.
rebooting both PCs. No dice.
tried mtp and ptp on device. Neither worked. Device was not recognized on MTP (used to be recognized by adb when it was on mtp.) device was recognized on ptp, but it was listed as "unauthorized"
tried to revoke usb debugging in settings on device. That option wasn't listed in developer options.
tried to clear adbkey on device and found out that my device still hadn't generated an adbkey file!
throughout this whole time, whenever I plugged in my device, the NSA fingerprint dialog box DID NOT APPEAR.
Questions, thoughts on potential solutions:
can I somehow unroot or go back to stock? I heard we can't do this anymore because it bricks our phones....
I feel like this has something to do with how my device never created an adbkeys file.

SOLUTION
I have been working on this today and I found a solution. I had read that downgrading/unrooting bricks our devices, and so I had ruled it out as an option. After further research I found that we can revert to stock without downgrading and avoid a brick. Since I have an H811 on 20o, I found firmware here and flashed it using LGUP, which you can find here. I suggest using this link to learn how to flash the firmware. After that, ADB worked fine and the NSA fingerprint dialog once again showed up on my device when I ran ADB. Good luck to any of you with the same problem!!! Reply if you need help.

Adb recognizes devices during phone on state, but not in fastboot.

Okay so now that I've scanned pretty much all of what the internet has to offer on this issue, I'm helpless and forced to write a new thread here about this.
Yes, a similar question has been replied to a million times before, but absolutely none of that helped, made no difference whatsoever.
So earlier, I was on the stock rom, with TWRP flashed and root access. But wanted to switch to the community build. Tried the twrp trick to install the CB but that didn't work, so flashed the stock OP3 rom and flashed community build.
All went fine, until I tried flashing back TWRP. Used the traditional ADB method of doing that, seemed to have flashed it but tried going into recovery only to be presented with a black screen. I got fed up of that trying to fix it for a whole day so I just left it, because I could still boot into the OS and that worked fine.
Fast forward to about a week later; somehow the flash didn't work and I still have stock recovery. Now I try flashing TWRP again, but I discover that my device doesn't get detected in fastboot. It absolutely refuses to.
It DOES, however, gets detected in the OS just fine.
I've tried every which way, absolutely NOTHING seems to work AT ALL.
- OEM unlocking is checked, if that makes a difference
- USB debugging is turned on
- Uninstalled all USB drivers related to the device, and installed them via device manager (but it gave me this error:
"the folder you specified doesn't contain a compatible software driver for your device. If the folder contains a driver, make sure it is designed to work with windows for x64-based systems)
seeing as I'm on an x64 version of Windows (its worked before with my Nexus 5, I swear)
- Tried it with different adb fastboot files, from all over the internet. All of them show just that blank space after I type in 'adb devices'
- Installed universal adb drivers.
- Samsung drivers.
- Obviously the official OnePlus drivers.
- Used Usbdeview to uninstall / force stop and re-installed the drivers.
- All in one tool
Now I'm thinking, I should try to re-lock the bootloader and unlock it again, or do like hard rest sort of things. I have no idea though, how this would affect the detection in fastboot.
Anyone have any ideas? Because I'm out of all of them, and so is most of internet.
TL;DR - Adb devices detects phone while booted in OS, but not in fastboot. Tried all methods, nothing works. Going to do lock bootloader then unlock it and try again, if not that then going to do a clean wipe and install the community build again, hoping that would work. Should I?

railpressureflip said:
Okay so now that I've scanned pretty much all of what the internet has to offer on this issue, I'm helpless and forced to write a new thread here about this.
Yes, a similar question has been replied to a million times before, but absolutely none of that helped, made no difference whatsoever.
So earlier, I was on the stock rom, with TWRP flashed and root access. But wanted to switch to the community build. Tried the twrp trick to install the CB but that didn't work, so flashed the stock OP3 rom and flashed community build.
All went fine, until I tried flashing back TWRP. Used the traditional ADB method of doing that, seemed to have flashed it but tried going into recovery only to be presented with a black screen. I got fed up of that trying to fix it for a whole day so I just left it, because I could still boot into the OS and that worked fine.
Fast forward to about a week later; somehow the flash didn't work and I still have stock recovery. Now I try flashing TWRP again, but I discover that my device doesn't get detected in fastboot. It absolutely refuses to.
It DOES, however, gets detected in the OS just fine.
I've tried every which way, absolutely NOTHING seems to work AT ALL.
- OEM unlocking is checked, if that makes a difference
- USB debugging is turned on
- Uninstalled all USB drivers related to the device, and installed them via device manager (but it gave me this error:
"the folder you specified doesn't contain a compatible software driver for your device. If the folder contains a driver, make sure it is designed to work with windows for x64-based systems)
seeing as I'm on an x64 version of Windows (its worked before with my Nexus 5, I swear)
- Tried it with different adb fastboot files, from all over the internet. All of them show just that blank space after I type in 'adb devices'
- Installed universal adb drivers.
- Samsung drivers.
- Obviously the official OnePlus drivers.
- Used Usbdeview to uninstall / force stop and re-installed the drivers.
- All in one tool
Now I'm thinking, I should try to re-lock the bootloader and unlock it again, or do like hard rest sort of things. I have no idea though, how this would affect the detection in fastboot.
Anyone have any ideas? Because I'm out of all of them, and so is most of internet.
TL;DR - Adb devices detects phone while booted in OS, but not in fastboot. Tried all methods, nothing works. Going to do lock bootloader then unlock it and try again, if not that then going to do a clean wipe and install the community build again, hoping that would work. Should I?
Click to expand...
Click to collapse
http://forum.xda-developers.com/showthread.php?t=3485186

Having the exact same Problems with my OP3 running everything stock 3.2.7 expect for the fact the device is unlocked...
Would love to hear how the problem can be solved!

ELoTRIX said:
http://forum.xda-developers.com/showthread.php?t=3485186
Click to expand...
Click to collapse
Hmmm Windows 7.
I can most certainly try that but the real question now is; how the hell did it work previously on my Windows 10 machine and refuses to work now? But at least I have a solution to try out, in the mean time! Thanks!

railpressureflip said:
Okay so now that I've scanned pretty much all of what the internet has to offer on this issue, I'm helpless and forced to write a new thread here about this.
Yes, a similar question has been replied to a million times before, but absolutely none of that helped, made no difference whatsoever.
So earlier, I was on the stock rom, with TWRP flashed and root access. But wanted to switch to the community build. Tried the twrp trick to install the CB but that didn't work, so flashed the stock OP3 rom and flashed community build.
All went fine, until I tried flashing back TWRP. Used the traditional ADB method of doing that, seemed to have flashed it but tried going into recovery only to be presented with a black screen. I got fed up of that trying to fix it for a whole day so I just left it, because I could still boot into the OS and that worked fine.
Fast forward to about a week later; somehow the flash didn't work and I still have stock recovery. Now I try flashing TWRP again, but I discover that my device doesn't get detected in fastboot. It absolutely refuses to.
It DOES, however, gets detected in the OS just fine.
I've tried every which way, absolutely NOTHING seems to work AT ALL.
- OEM unlocking is checked, if that makes a difference
- USB debugging is turned on
- Uninstalled all USB drivers related to the device, and installed them via device manager (but it gave me this error:
"the folder you specified doesn't contain a compatible software driver for your device. If the folder contains a driver, make sure it is designed to work with windows for x64-based systems)
seeing as I'm on an x64 version of Windows (its worked before with my Nexus 5, I swear)
- Tried it with different adb fastboot files, from all over the internet. All of them show just that blank space after I type in 'adb devices'
- Installed universal adb drivers.
- Samsung drivers.
- Obviously the official OnePlus drivers.
- Used Usbdeview to uninstall / force stop and re-installed the drivers.
- All in one tool
Now I'm thinking, I should try to re-lock the bootloader and unlock it again, or do like hard rest sort of things. I have no idea though, how this would affect the detection in fastboot.
Anyone have any ideas? Because I'm out of all of them, and so is most of internet.
TL;DR - Adb devices detects phone while booted in OS, but not in fastboot. Tried all methods, nothing works. Going to do lock bootloader then unlock it and try again, if not that then going to do a clean wipe and install the community build again, hoping that would work. Should I?
Click to expand...
Click to collapse
You need modified twrp by @eng.sdk.
http://forum.xda-developers.com/showpost.php?p=68691560&postcount=56

I am having a similar issue. I have a brand new OP3. Everything stock. I'm attempting to unlock the bootloader and have found that while ADB recognises the phone, Fastboot doesn't. I'm pretty sure it's a driver issue and I have no idea how to fix.

Hello
Everything is working good
it seems to be a problem with adb Windows 10 IDK
, it is better to do it on Windows 7
Follow this :
http://forum.xda-developers.com/oneplus-3/how-to/oneplus-3-how-to-unlock-bootloader-t3398733

abhi0502 said:
You need modified twrp by @eng.sdk.
http://forum.xda-developers.com/showpost.php?p=68691560&postcount=56
Click to expand...
Click to collapse
I'm afraid you've missed the point, my friend.
If the phone does not get detected in the fastboot, it means I cannot flash anything, period. No original TWRP, no modified TWRP.

I had this exact issue and fixed it.
Fastboot would never see my device, no matter which driver package I tried or no matter how I tried to install or force the correct drivers. Turns out Windows 10 (and Windows 8) has a feature that completely prevents installation of unsigned drivers, which blocks the fastboot driver. If you're seeing "Kedracom" or "Android Device" in the device manager, then your driver is NOT actually installed. This is true even if Windows doesn't throw you an error message during install, or if you appear to force the installation. Even though it looks like you're doing the install correctly, Windows just ignores your unsigned drivers.
You need to temporarily disable the security feature to permit installation of unsigned drivers. This involves invoking a special restart function. Here's the howto for Win10: http://www.howtogeek.com/167723/how-...igned-drivers/
Once you've done this, on the next reboot you can do a forced install of the unsigned fastboot drivers you downloaded for the OP3. And simply rebooting your computer restores the security feature.

It's mostly because of the windows security over unsigned drivers.. Try the above method or just the cmd way..
Sent from my Xiaomi Mi 5 using XDA Labs

G4 no fastboot and recovery mode

Hello,
today I have a problem with my g4. When I first got this phone 2 years ago I instantly unlocked bootloader, installed supersu, xposed etc and I had no problems at all with this.
But couple weeks ago somethings happened to my snapchat so today I tried to unroot to login to my account on sc. Then i checked that I have to uninstall xposed framework too, but to do this from xposed installer app, root is needed. I thought "no problem, I will install root briefly, uninstall xposed, unroot and login to snapchat". Then I met first obstacle. I don't have recovery mode in phone. when I connect g4 by usb to pc and use adb (by typing adb reboot recovery) my phone reboots and shows green dead android with red triangle. I have to remove the battery to get phone back to life. I remembered that i always used fastboot commands to boot into custom recovery instead of installing TWRP, because flashing it never worked. But now when I try to execute any fastboot command, it only shows me "waiting for any device" in cmd. what do I have to do now? all essential drivers are installed on my pc. phone is showed as "LGE Mobile adb interface" in device manager. when I enter "adb reboot fastboot" it only reboots my phone and nothing else. Does anybody know a solution? I wouldn't like to wipe my g4 from all data. I have read many pages on google and nothing helps. I've tried fastboot on 2 different computers, one with usb 3.0 and one with 2.0 and results are the same. If someone could help me, thanks in advance.

dziedziol said:
Hello,
today I have a problem with my g4. When I first got this phone 2 years ago I instantly unlocked bootloader, installed supersu, xposed etc and I had no problems at all with this.
But couple weeks ago somethings happened to my snapchat so today I tried to unroot to login to my account on sc. Then i checked that I have to uninstall xposed framework too, but to do this from xposed installer app, root is needed. I thought "no problem, I will install root briefly, uninstall xposed, unroot and login to snapchat". Then I met first obstacle. I don't have recovery mode in phone. when I connect g4 by usb to pc and use adb (by typing adb reboot recovery) my phone reboots and shows green dead android with red triangle. I have to remove the battery to get phone back to life. I remembered that i always used fastboot commands to boot into custom recovery instead of installing TWRP, because flashing it never worked. But now when I try to execute any fastboot command, it only shows me "waiting for any device" in cmd. what do I have to do now? all essential drivers are installed on my pc. phone is showed as "LGE Mobile adb interface" in device manager. when I enter "adb reboot fastboot" it only reboots my phone and nothing else. Does anybody know a solution? I wouldn't like to wipe my g4 from all data. I have read many pages on google and nothing helps. I've tried fastboot on 2 different computers, one with usb 3.0 and one with 2.0 and results are the same. If someone could help me, thanks in advance.
Click to expand...
Click to collapse
Try another Cable. Even my original LG cable isnt working with fastboot/adb.
have you tried: https://forum.xda-developers.com/g4/general/guide-how-to-enter-fastboot-mode-t3239537
some more Information about Your Phone. usu´d or nornmally unlooked. Stock rom?

uweork said:
Try another Cable. Even my original LG cable isnt working with fastboot/adb.
have you tried: https://forum.xda-developers.com/g4/general/guide-how-to-enter-fastboot-mode-t3239537
some more Information about Your Phone. usu´d or nornmally unlooked. Stock rom?
Click to expand...
Click to collapse
Tried with another cable and nothing changes.
I tried to do this method you sent. So when I enter download mode it goes into "firmware update" after couple of seconds, my phone isn't detected on pc and the first command in console "Send_Command.exe \\.\COMx" returns "FAIL".
My G4 (H815) is stock rom, bootloader unlocked normally, didn't do any usu or anything like this. I have only rooted it with supersu 2 times (one time maybe a 1,5year ago i log out from snapchat and had to unroot and root again), installed xposed framework and did nothing else. I don't know how is it possible that I used fastboot on this phone then and now I can't do it. Half a year ago I've installed custom rom on friend's G2 and installed some programs etc. on my pc (because installing this rom didn't went that well and I had to flash stock .kdz or something like that through LGUP/LG bridge/lg flash tool, I don't remember) and I thought that it did some mess but when I tried to use fastboot on another PC, where I've installed drivers freshly, the result was the same.
So what is about "firmware update"? It is obviously stuck on 0% and I have to remove the battery to leave this mode.

dziedziol said:
Tried with another cable and nothing changes.
I tried to do this method you sent. So when I enter download mode it goes into "firmware update" after couple of seconds, my phone isn't detected on pc and the first command in console "Send_Command.exe \\.\COMx" returns "FAIL".
My G4 (H815) is stock rom, bootloader unlocked normally, didn't do any usu or anything like this. I have only rooted it with supersu 2 times (one time maybe a 1,5year ago i log out from snapchat and had to unroot and root again), installed xposed framework and did nothing else. I don't know how is it possible that I used fastboot on this phone then and now I can't do it. Half a year ago I've installed custom rom on friend's G2 and installed some programs etc. on my pc (because installing this rom didn't went that well and I had to flash stock .kdz or something like that through LGUP/LG bridge/lg flash tool, I don't remember) and I thought that it did some mess but when I tried to use fastboot on another PC, where I've installed drivers freshly, the result was the same.
So what is about "firmware update"? It is obviously stuck on 0% and I have to remove the battery to leave this mode.
Click to expand...
Click to collapse
Try installing "adb universal drivers".
Also in your computer device manager, with the phone connected, uninstall the device, adb device, modem everything related with the phone. Reinstall and try it after install the universal drivers.
Hope it works, good luck!

RuedasLocas said:
Try installing "adb universal drivers".
Also in your computer device manager, with the phone connected, uninstall the device, adb device, modem everything related with the phone. Reinstall and try it after install the universal drivers.
Hope it works, good luck!
Click to expand...
Click to collapse
Uninstalled everything lg-related from device manager, uninstalled everything lg/android-related through revo uninstaller, installed adb universal drivers, lg usb drivers, everything seems fine, when I type "adb devices" in cmd it shows my phone but, again, when I enter something related to fastboot, it only shows <waiting for any device>.
Is it even possible?? I have not seen any cases like mine in internet - somebody's phone every time was else bricked or somebody would try to flash something and errors like that happened, but I have used fastboot many times on G4 and G2, didn't reinstall windows and everything worked! Why I can't access recovery mode (dead android with red triangle) or enter fastboot or do something in download mode? What could happened?! Is it possible to fix this without wiping data from my G4? I haven't done factory reset for very long time and copying tens of thousands of photos and videos, quickmemo notes, music, voice recordings, chrome bookmarks and everything else to my PC would be a big pain for me.
After all, thanks for replies, and I hope that we will find solution for this.

dziedziol said:
Uninstalled everything lg-related from device manager, uninstalled everything lg/android-related through revo uninstaller, installed adb universal drivers, lg usb drivers, everything seems fine, when I type "adb devices" in cmd it shows my phone but, again, when I enter something related to fastboot, it only shows <waiting for any device>.
Is it even possible?? I have not seen any cases like mine in internet - somebody's phone every time was else bricked or somebody would try to flash something and errors like that happened, but I have used fastboot many times on G4 and G2, didn't reinstall windows and everything worked! Why I can't access recovery mode (dead android with red triangle) or enter fastboot or do something in download mode? What could happened?! Is it possible to fix this without wiping data from my G4? I haven't done factory reset for very long time and copying tens of thousands of photos and videos, quickmemo notes, music, voice recordings, chrome bookmarks and everything else to my PC would be a big pain for me.
After all, thanks for replies, and I hope that we will find solution for this.
Click to expand...
Click to collapse
You could Check if FWUL from SteadfasterX is helping You out with your Problem.
https://forum.xda-developers.com/an.../live-iso-adb-fastboot-driver-issues-t3526755
With the Installed Salt You cann Backup your Device.

dziedziol said:
Uninstalled everything lg-related from device manager, uninstalled everything lg/android-related through revo uninstaller, installed adb universal drivers, lg usb drivers, everything seems fine, when I type "adb devices" in cmd it shows my phone but, again, when I enter something related to fastboot, it only shows <waiting for any device>.
Is it even possible?? I have not seen any cases like mine in internet - somebody's phone every time was else bricked or somebody would try to flash something and errors like that happened, but I have used fastboot many times on G4 and G2, didn't reinstall windows and everything worked! Why I can't access recovery mode (dead android with red triangle) or enter fastboot or do something in download mode? What could happened?! Is it possible to fix this without wiping data from my G4? I haven't done factory reset for very long time and copying tens of thousands of photos and videos, quickmemo notes, music, voice recordings, chrome bookmarks and everything else to my PC would be a big pain for me.
After all, thanks for replies, and I hope that we will find solution for this.
Click to expand...
Click to collapse
<waiting for any device> because if windows don't recognizes the device as it should adb will never "see" it.
While on the process, pay attention to the device manager. When you get the message in cmd of <waiting for any device>, uninstall your device and make device manager search for devices.
If still shows you as the same device and adb still waiting, you might have to uninstall the device and install it manually choosing from a list. Now I don't remember how it is suppose to be detected...
During install and uninstall don't disconnect the device from the computer, and remember, use a USB2 port.
I already got that several time. Took me time but that's how I managed to fix it.

okay, guys, it is a shame for me... but I worked out what is wrong with my phone.. maybe not with my phone, but what is wrong with me.
all I needed to do to launch a fastboot was type "adb reboot bootloader" and everything is fine now.
Sorry that you had to give me so much tips and this problem turned to be my stupid mistake, but I'm glad that i won't have to install linux and play with virtual machines to repair my phone
Anyway, thanks for your kindness and will to help, greetings for everyone!
@edit: Turns out that i have one more question. I want to uninstall xposed framework. But there are many versions of uninstaller on their site. Is there any risk that i will "break" my G4 if I use the newest one? I have xposed version 87 and I don't want to do something stupid. thanks in advance.

somebody knows? if I can use the newest version of uninstaller no matter which version of xposed framework im using?