Hi guys,
I was running CloudyG3 2.5 on my D855. Today I wanted to go back to stock using LG Flash Tool with D85520h firmware file (lollipop) (in Windows 10). It got stuck at 4%. After waiting for close to an hour, I just unplgged the device. Now when I power it up, I get the secure boot error message and it starts blinking the notification LED (alternating red and blue). Going into download mode also brings up the same blinks, as does attempting to go into recovery mode.
All the threads I have gone to seem to assume that the phone can boot, or enter recovery mode or enter download mode. My phone can do neither.
I desperately need help.
Thanks in advance
ling_c said:
Hi guys,
I was running CloudyG3 2.5 on my D855. Today I wanted to go back to stock using LG Flash Tool with D85520h firmware file (lollipop) (in Windows 10). It got stuck at 4%. After waiting for close to an hour, I just unplgged the device. Now when I power it up, I get the secure boot error message and it starts blinking the notification LED (alternating red and blue). Going into download mode also brings up the same blinks, as does attempting to go into recovery mode.
All the threads I have gone to seem to assume that the phone can boot, or enter recovery mode or enter download mode. My phone can do neither.
I desperately need help.
Thanks in advance
Click to expand...
Click to collapse
you go to this page (http://forum.xda-developers.com/sprint-lg-g3/general/guide-fix-hard-brick-recovery-guide-t3132359)
i also same your problem but i ald fix that.
thurasisyein said:
you go to this page (http://forum.xda-developers.com/sprint-lg-g3/general/guide-fix-hard-brick-recovery-guide-t3132359)
i also same your problem but i ald fix that.
Click to expand...
Click to collapse
Thanks a lot mate. I used the willcracker tool attached in the OP of the thread and it worked like a charm. My phone could go into the Qualcomm HS-USB mode but one of the following factors could have been at play:
1. The BoardDiag tool I was used was fake (as mentioned in the thread you referred me to.
2. The PC I was working on has all ports as USB 3.0 (I'm not sure if that was issue or the fact that I had other devices connected-- just a mouse adaptor, but I could see my phone in Device Manager)
So, I went ahead and changed all of the above: used the newly-found BoardDiag (willcracker), on a another PC with a USB 2.0 port and made sure no other devices were connected.
My phone is now back to life!
Related
Hello, first I'd like to thank you for your time reading this.
Note: I've searched the forums a lot, even for other LG Devices (G2 for ex) but I couldn't find a solution.
Trying to flash CM12 by _infected (amazing rom, working as a daily driver on my other lg pad btw) and messed up something on TWRP.
-First trying to do a Factory Reset via TWRP gave me "failed to mount /data" and "/system" I rebooted and the device went straight to TWRP Recovery, I rebooted again, this time making sure I selected "Reboot to System" and it went again to TWRP Recovery...
- I did another wipe, this time wiped everything (all checkboxes in TWRP), reboot and... no boot...
Now my LG Pad is at the following State:
- Black Screen (No LG Logo)
- Connecting USB to Windows gives the "connected sound"
- Adb doesnt find device (driver was installed and working).
- Device Manager "refreshes" on USB plug but doesnt show the device (or I can't find it?).
- Holding Power on the tablet while USB plugged to Windows gives the "disconnected sound" -> "connected sound" -> "connected sound".
- Can't boot into Download Mode.
- Can't turn off the Tablet... only Reboots holding Power key.
Please? Any help?
What can I do?
Is warranty void at this point?
Thank you very much for any help you can provide.
I have a G pad in the same situation, and I wasn't able to fix it. I managed to pick up another cheap one, but I'll follow this thread in case you get an answer.
You have to find a way to get it into download mode or you wont be able to fix it with LG Tool
What did you mess up, and how did you install twrp ? Also what twrp version abd base.
mekoneko said:
What did you mess up, and how did you install twrp ? Also what twrp version abd base.
Click to expand...
Click to collapse
For me personally, I assumed it'd be as easy as the twrp page makes it out to be , or my nexus 4 was, so I just went for it. I ran into that secure boot error with twrp, and rebooted back into stock. There was an OTA update, so I did it (stupid I now realise) and that bricked it on reboot. It won't turn on at all. If i plug into USB on a computer it OCCASIONALLY brings something up on the screen, the LG logo I think or something, but I cannot for the life of me get it into download mode. It's at home right now, so ic anot remmeber the exact thing it shows on screen, but almost certainly not download mode, and none of the hardware buttons seem to be responsive for doing factory resets or download or anything.
I managed to send the LG G Pad to warranty and got a new one... Lucky me...
Guess that if we can't get into DL mode they can't either.
However after much investigation I've realized that the problem was a corrupted system partition...
Hi guys, so my problem is I was installing a new rom on my rooted D855. everything was going along fine but then the process stalled. I left it running for 15 - 20 minutes but it was still on 33%. I tried holding the power button in desperation which shut the thing down. Now when I try to factory reset it goes to the prompt screen, I answer yes, then it asks me to confirm. from there however it goes to LG splash screen and eventually a black screen with Fastboot mode started. -reset- portcharge -reset- portcharge fastboot: processing commands in the top left corner. That's it.. If I try download mode it goes to the download screen and then to the black screen as described above.
Sounds pretty ordinary but if there is an answer out there I am sure one of you guys will know it.
TIA
i had some similar other issue and the only way i got out of it, is by using the lg flashtool 2014 and the KDZ file appropriate to your version
there is a thread with a step by step instructions.
you launch the flashtool, then insert the kdz file (original stock rom) then you put your phone into download mode (making sure in windows/controlpanel/devicemanager/ports - comp port 41 for the device driver)
you press volume up and plug it into the pc, the pc sees the phone and it starts reflashing the custom rom to your cell.
i presume that as soon as your download mode is working by flashing whatever command is corrupt and makes your phone black should be bypassed by then
i hope it helps - look for the thread how to flash the lg
Thanks I'll give it a shot. Not sure device manager is seeing it properly. I'll have a play and see. Thanks again for the reply
O.K here's the thing, my phone is seen in device manager as a Samsung Android Phone. Under the details tab it shows it connected via USB Modem Phone ADB Port. There is no option to change the port to 41. Anybody who can help I would be very grateful......
I have just flash the custom 5.0.2 ROM using philz touch 6.48.4.
After I flashed the ROM, I reboot to the philz recovery and flashed back to cwm 6.0.4.8.
However, the device stuck on the LG logo screen.
I have try to enter Download mode/Emergence mode/Hard reset mode/Recovery, but all of them I cannot go into.
Please help! Thank you for your helping!!
pchuen said:
I have just flash the custom 5.0.2 ROM using philz touch 6.48.4.
After I flashed the ROM, I reboot to the philz recovery and flashed back to cwm 6.0.4.8.
However, the device stuck on the LG logo screen.
I have try to enter Download mode/Emergence mode/Hard reset mode/Recovery, but all of them I cannot go into.
Please help! Thank you for your helping!!
Click to expand...
Click to collapse
Your boot loader is broken. Gonna have to get to the down load mode and reinstall either the or the stock. You can probably flash the recovery with .IMG file with lg flashing tool. Nerdy blond's twrp is one of those files that you can use. You can even try installing it first with the adb shell command, you can get the instructions at the same place where you download.
http://forum.xda-developers.com/showthread.php?t=3144369
hawkwind212 said:
Your boot loader is broken. Gonna have to get to the down load mode and reinstall either the or the stock. You can probably flash the recovery with .IMG file with lg flashing tool. Nerdy blond's twrp is one of those files that you can use. You can even try installing it first with the adb shell command, you can get the instructions at the same place where you download.
http://forum.xda-developers.com/showthread.php?t=3144369
Click to expand...
Click to collapse
Thank you for replying.
I cannot do anythings since I cannot enter into download mode.
I pressed volume key + and - and insert the usb cable to computer. There is nothing happened, computer dose not show the devices attached and the phone stay in the LG logo screen.
Also, I cannot use adb commands to force the phone enters into download mode as it shows nothings under "List of devices".
Is there any methods I can go into the download mode???
Thank you!
pchuen said:
Thank you for replying.
I cannot do anythings since I cannot enter into download mode.
I pressed volume key + and - and insert the usb cable to computer. There is nothing happened, computer dose not show the devices attached and the phone stay in the LG logo screen.
Also, I cannot use adb commands to force the phone enters into download mode as it shows nothings under "List of devices".
Is there any methods I can go into the download mode???
Thank you!
Click to expand...
Click to collapse
If your phone shows LG start screen, it should go into Download mode. I had similar problem few days ago while I was testing some kernel patches, it just froze on the LG screen. Solution was to unplug it, remove it's battery, SIM & SD (you don't have to remove SIM & SD, I just work that way) , make sure it's off, return battery back, press Vol + & Vol - at the same time and plug-in the USB cable.
Before that, make sure you have installed LG Unified driver (can be obtained via LG's software from support site), because without that Windows won't recognise your device.
After that, once you make your phone usable with Freegee/whatever you use to install initial recovery, flash official TWRP, because others are too old - that Philz CWM is old but still working with Lollipop but not work good and is tends to lock itself into a bootloop if you use hardware keys to enter; that other one, from GPRO_recovery APK is not supported and not working well (for me since day one), so it should be replaced as soon as possible.
Also, I can suggest you to flash your phone from stock 4.1 (not KitKat), root, flash recovery via freegee and after reboot update to latest official TWRP via Flashify.
hawkwind212 said:
Your boot loader is broken. Gonna have to get to the down load mode and reinstall either the or the stock. You can probably flash the recovery with .IMG file with lg flashing tool. Nerdy blond's twrp is one of those files that you can use. You can even try installing it first with the adb shell command, you can get the instructions at the same place where you download.
http://forum.xda-developers.com/showthread.php?t=3144369
Click to expand...
Click to collapse
ShadySquirrel said:
If your phone shows LG start screen, it should go into Download mode. I had similar problem few days ago while I was testing some kernel patches, it just froze on the LG screen. Solution was to unplug it, remove it's battery, SIM & SD (you don't have to remove SIM & SD, I just work that way) , make sure it's off, return battery back, press Vol + & Vol - at the same time and plug-in the USB cable.
Before that, make sure you have installed LG Unified driver (can be obtained via LG's software from support site), because without that Windows won't recognise your device.
After that, once you make your phone usable with Freegee/whatever you use to install initial recovery, flash official TWRP, because others are too old - that Philz CWM is old but still working with Lollipop but not work good and is tends to lock itself into a bootloop if you use hardware keys to enter; that other one, from GPRO_recovery APK is not supported and not working well (for me since day one), so it should be replaced as soon as possible.
Also, I can suggest you to flash your phone from stock 4.1 (not KitKat), root, flash recovery via freegee and after reboot update to latest official TWRP via Flashify.
Click to expand...
Click to collapse
Thank you for your detail reply.
I have tried to reinstall the LG driver and try to enter download mode again.
The screen is still stuck on LG logo and I cannot find the device in hardware manager (cannot recognize it).
I cannot do anythings until it can recognize it.
(Is it the bootloader is broken? and can I fix it?)
Thank you very much and waiting for your reply soon.:good:
pchuen said:
Thank you for your detail reply.
I have tried to reinstall the LG driver and try to enter download mode again.
The screen is still stuck on LG logo and I cannot find the device in hardware manager (cannot recognize it).
I cannot do anythings until it can recognize it.
(Is it the bootloader is broken? and can I fix it?)
Thank you very much and waiting for your reply soon.:good:
Click to expand...
Click to collapse
Which version of Windows are you using? It should be displayed under Serial ports in Device manager (named something like LGE Serial device) and LGFlashTool should recognise it immediately. I can't make you a screenshot/check for real name because I'm running Linux right now and can't reboot.
Also, try with another cable/port, remove all other android drivers you may have (Samsung's, Google's...) and disable antivirus.
ShadySquirrel said:
Which version of Windows are you using? It should be displayed under Serial ports in Device manager (named something like LGE Serial device) and LGFlashTool should recognise it immediately. I can't make you a screenshot/check for real name because I'm running Linux right now and can't reboot.
Also, try with another cable/port, remove all other android drivers you may have (Samsung's, Google's...) and disable antivirus.
Click to expand...
Click to collapse
It does not work on Windows 7 and XP.
I did not find any LGE XXX under Serial ports part.
Thank you!
pchuen said:
It does not work on Windows 7 and XP.
I did not find any LGE XXX under Serial ports part.
Thank you!
Click to expand...
Click to collapse
Hm.... Phone shows that it have entered download mode? Black screen, centered gray message and "DOWNLOAD MODE" red text?
ShadySquirrel said:
Hm.... Phone shows that it have entered download mode? Black screen, centered gray message and "DOWNLOAD MODE" red text?
Click to expand...
Click to collapse
No... nothing happens, just showing LG logo...
pchuen said:
No... nothing happens, just showing LG logo...
Click to expand...
Click to collapse
OK, it doesn't enter download mode. So, step by step:
- remove battery and leave it for 15-30 seconds, return battery
- press Vol+ and Vol- at the same time and keep them pressed,
- plug USB cable in while keys are pressed
It should immediately put you into download mode, with no LG screen, just black screen with gray box and red text I've described to you.
ShadySquirrel said:
OK, it doesn't enter download mode. So, step by step:
- remove battery and leave it for 15-30 seconds,
- press Vol+ and Vol- at the same time and keep them pressed,
- plug USB cable in while keys are pressed
It should immediately put you into download mode, with no LG screen, just black screen with gray box and red text I've described to you.
Click to expand...
Click to collapse
I understand what download mode screen is.
I followed your methods, bur I still cannot enter it and the computer cannot recognize that.
Sorry for disturbing :crying:
pchuen said:
I understand what download mode screen is.
I followed your methods, bur I still cannot enter it and the computer cannot recognize that.
Sorry for disturbing :crying:
Click to expand...
Click to collapse
So, whatever you try to do, phone just shows LG logo, not even a message in an upper left corner?
I'm running out of ideas. I have exact same variant (E988) but only time it didn't want to enter download mode this way was when cable I was using was broken...
ShadySquirrel said:
So, whatever you try to do, phone just shows LG logo, not even a message in an upper left corner?
I'm running out of ideas. I have exact same variant (E988) but only time it didn't want to enter download mode this way was when cable I was using was broken...
Click to expand...
Click to collapse
I have changed the cable, but it is the same.
Hey everyone,
We have an LG G3 D855 here which has been interrupted midway through flashing a KDZ file,
Powering on the device gives us,
"Cause : Boot certification verify (secure booting error)"
Followed by the screen going off and the blue red LED flashing endlessly.
Download mode does not work,
Recovery mode does not work,
However, the factory reset screen appears, but when selecting yes it reverts to the LG logo and reboots.
Here is a screen shot of what appears in device manager on my PC after I attempt to enter download mode.
As you can see, it is "QHSUSB_BULK" in device manager.
We have tried adapting this guide for the G2 with Ubuntu, but the device is not recognized by Ubuntu. http://forum.xda-developers.com/showthread.php?t=2582142
If we can get into fastboot somehow we will be fine, but nothing seems to be responding. Any advice would be fantastic.
We also have another idea, of super hard bricking the device somehow so that we can follow this tested method of getting out of the brick,
http://forum.xda-developers.com/lg-g3/general/fix-unbrick-lg-g3-stuck-qualcomm-hs-usb-t2933853 not sure how to get either of these though so some help would be great.
The same problem has been described here, http://forum.xda-developers.com/lg-g3/help/lg-g3-d855-rooted-download-mode-t3003988
EDIT : After 10 hours of working on this problem we found the solution and posted our fix and explanation here http://forum.xda-developers.com/lg-...nload-mode-t3273824/post64377399#post64377399
Thanks to all parties involved.
Orcam said:
Hey everyone,
We have an LG G3 D855 here which has been interrupted midway through flashing a KDZ file,
Powering on the device gives us,
"Cause : Boot certification verify (secure booting error)"
Followed by the screen going off and the blue red LED flashing endlessly.
Download mode does not work,
Recovery mode does not work,
However, the factory reset screen appears, but when selecting yes it reverts to the LG logo and reboots.
Here is a screen shot of what appears in device manager on my PC after I attempt to enter download mode.
As you can see, it is "QHSUSB_BULK" in device manager.
We have tried adapting this guide for the G2 with Ubuntu, but the device is not recognized by Ubuntu. http://forum.xda-developers.com/showthread.php?t=2582142
If we can get into fastboot somehow we will be fine, but nothing seems to be responding. Any advice would be fantastic.
We also have another idea, of super hard bricking the device somehow so that we can follow this tested method of getting out of the brick,
http://forum.xda-developers.com/lg-g3/general/fix-unbrick-lg-g3-stuck-qualcomm-hs-usb-t2933853 not sure how to get either of these though so some help would be great.
The same problem has been described here, http://forum.xda-developers.com/lg-g3/help/lg-g3-d855-rooted-download-mode-t3003988
Click to expand...
Click to collapse
Have a look here >> http://forum.xda-developers.com/sprint-lg-g3/general/guide-fix-hard-brick-recovery-guide-t3132359 <<
Follow the guide above
tallman43 said:
Have a look here >> http://forum.xda-developers.com/sprint-lg-g3/general/guide-fix-hard-brick-recovery-guide-t3132359 <<
Click to expand...
Click to collapse
Thanks mate, are there no software alternatives to this problem? We have been looking literally for hours.
It works! I have found a diffrent package at web. The "Device is not in DL mode" issue is much better with! If the DL breaks, reject the USB-cable and klick start again the process should start without probs. For prevent the app to freeze exclude cust.mbn, system.mbn, userdata.mbn, cache.mbn every .mbn bigger then 50mb. This files we can flash later with Flashtool after the device is back to life
Files: https://mega.nz/#!fRwD1a4Z!Et6aea3XInKW4frrNs-GqGz5diIQdjNBjOg6uTiG6Hk
Hope it would help...
greets and very Christmas to all!
Hello all,
I've done a lot of googling and searching on these forums and I'm having no luck. Hopefully by asking I can get some headway.
I was attempting to restore to stock rom. At 17% of the process using LGFlashTool 1.8.6 the tool gave me an error 'Unable to Communicate with phone' after about 10 minutes of no progress. I exited the LGFlashTool program and ran it again and now it fails saying 'Cant' change to download mode". If I turn the phone off and then press Vol+ and plug in my cable it just goes to the Firmware Update screen. My phone *IS* detected properly in the device manager as LGE Andriod MTP Device and under ports as LGE Mobile USB Serial Port (COM41). If I go into recovery (Vol- and power) it asks if I want to do the restore - but it doesn't actually do anything once I say yes twice. Just sits at the firmware update screen at 0%.
I looked at this post (http://forum.xda-developers.com/lg-g3/general/unbrick-lg-g3-qhsusbbulk-qualcomm-9008-t3072091) but it appears to be either for a different phone or different problem (showing in device manager as a bulk device - mine is not doing that). Frankly I don't want to make things worse (if that's possible)
Does anyone have a way that I can restore the download mode for this D852 phone? I'm hoping if I can get download mode to work again I can reflash the stock rom. I don't care about the data on the phone at this point.
I'm willing to send some $$$ via paypal to whomever can get me back up and running! Thanks
Valgore said:
Hello all,
I've done a lot of googling and searching on these forums and I'm having no luck. Hopefully by asking I can get some headway.
I was attempting to restore to stock rom. At 17% of the process using LGFlashTool 1.8.6 the tool gave me an error 'Unable to Communicate with phone' after about 10 minutes of no progress. I exited the LGFlashTool program and ran it again and now it fails saying 'Cant' change to download mode". If I turn the phone off and then press Vol+ and plug in my cable it just goes to the Firmware Update screen. My phone *IS* detected properly in the device manager as LGE Andriod MTP Device and under ports as LGE Mobile USB Serial Port (COM41). If I go into recovery (Vol- and power) it asks if I want to do the restore - but it doesn't actually do anything once I say yes twice. Just sits at the firmware update screen at 0%.
I looked at this post (http://forum.xda-developers.com/lg-g3/general/unbrick-lg-g3-qhsusbbulk-qualcomm-9008-t3072091) but it appears to be either for a different phone or different problem (showing in device manager as a bulk device - mine is not doing that). Frankly I don't want to make things worse (if that's possible)
Does anyone have a way that I can restore the download mode for this D852 phone? I'm hoping if I can get download mode to work again I can reflash the stock rom. I don't care about the data on the phone at this point.
I'm willing to send some $$$ via paypal to whomever can get me back up and running! Thanks
Click to expand...
Click to collapse
What happens when u just power up the phone ?
Thanks for the reply.
If I shut the phone down (by pulling battery) then plug it back in and just power it on, I get the LG logo then it goes to the firmware update screen with 'USER B84" in the box below the progress bar. Progress bar never moves. I get to this screen whether I start it in recovery (which is just the factory recov - looks like during the initial 17% it wiped out my TWRP), attempt to start it in download mode (I do not get the download mode screen with the blue dots anymore), or regularly by just holding the power button.
ok
Dont plug it into the computer and try to power it up what does ot do?
Same thing.
read this
http://forum.xda-developers.com/lg-g3/help/lg-g3-bricked-tried-everything-experts-t2852962 this might help
pacods61 said:
http://forum.xda-developers.com/lg-g3/help/lg-g3-bricked-tried-everything-experts-t2852962 this might help
Click to expand...
Click to collapse
Ok that didn't work for me but I did try the LGFlashTool using Board DL instead of Upgrade DL and it was moving a bit. Finally got to 10% and failed at 574 sec with the error "We can't communicate with Phone". I am using the cable that came with the phone. It isn't damaged or anything.
Here's what is shows in the LG Flashtool window (this is port 1 (com41)
Code:
PID: BS09S150309001007
IMEI: <myimei>
Model: D852
DLL: D852
BIN: <correct bin file from stock roms>
SWV: LGD852AT-01-V20C-302-720-FEB-04-(cuts off here can't read rest)
SWOV: LGD852AT-00-V20C-RGS-CA-FEB-04(cuts off here can't read rest)
Initializing
USB Connection Established
Start Download
LAF: Bin_User_Mode
PRIMARYGPT
MODEM
LAF:Bin_User_Mode
PRIMARYGPT
LAF:Bin_User_Mode
PRIMARYGPT
MODEM
[14: 7:28) We can't communicate with phone
00000064
On the phone it shows COM41 under the usb icon on under firmware update and 0% progress. In the box below it says:
Code:
F USER 50.0 A50.0 B70 UHS
S U LG-D852 04.4.2 Hrev_10
D85210b
D85210b
That's it. Should I leave the phone connected at this point or unplug it? Device still shown in device manager (have had it up beside the LG Flashtool window the whole time. I do see it refresh from time to time but the contents dont' seem to change at all.
Ok so I left this over night and when I checked the phone this morning it's different but I don't think it's good.
Looks like it proceeded but ended with:
FBOOT Check
FBOOT Complete Time [0s ] 1th try
Factory Reset Flag = 2
Factory Reset Flag Check Fail!!!
And my phone has a blue screen with Factory Reset Status and a big red '2'
Now what do I do?
Some further information.
If I run the LGFlashTool in Board DL action mode, it seems like the process works but I end up with the red 2 on the screen. But I don't get 'can't change to download mode' or 'cannot communicate with phone' errors.
However if I choose Upgrade DL action mode, then I get 'can't change to download mode' or cannot communicate with phone'. ARGH. What gives?
I have tried things like fresh restarts (restarting PC), restarting the LG FlashTool between attempts, not restarting flashtool, etc. I can't seem to find the sweet spot.
here
http://forum.xda-developers.com/sprint-lg-g3/help/fix-bricked-lg-g3-ls990-stuck-fastboot-t3084562 another tutorial to try
Thanks, but no dice.
I don't get fastboot options, and if i download and attempt to use fastboot, it shows no devices.
Also, when following the steps for the BOARD DL option in the lg flashtool, it goes through the process but I get no ATT screen. Nor do I get the option to tap OK or Normal - as soon as my device reboots after the flash, it gives me a MINI OS (iirc) screen with a bunch of vertical bars below it moving up and down then it changes to the Factory Reset screen with the number 2.
last one lol
http://androidforums.com/threads/ho...-2-lg-g3-d855-twn-32-gb-problem-fixed.911271/ i found one more that could help it said to use a jdz not a tot hope it helps if not sry
Thanks - I'm going to give this a try, however I can't finda .kdz file for my phone (canada/rogers D852 LG G3) - the links in that post that link to firmware is for a tot file. Does anyone have a link to the KDZ?
Hi, I'm having the exact same problem now, where the phone only boots to the Firmware Update screen. Did you manage to fix it?
Indeed.
I used the KDZ method pacods61 posted last, but I had trouble actually finding kdz firmware. With some help I finally managed to do so from here: http://devtester.ro/projects/lg-firmwares/country.php?country=Canada
Direct link for D852 Rogers Lolipop 5.0.1: http://csmgdl.lgmobile.com/dn/downloader.dev?fileKey=FWF448V332CPAKX8CEA4UCE/D85220g_00_1205.kdz