it was all ok.with pays Rom but since I started flashing froyo sense roms I am getting strange issues: as I flash it is all ok with the 3g hsdpa connection but after a second reboot I lose the 3g and I am unable to connect to internet without wifi.
I am sure to do it properly and also using the correct radio but I cannot sort this out any help ?thanks
Have you checked that you APN's are correct?
Ok i can flash any of the cm9 roms and have full signal in places i know i should have full signal. I use straight talk att sim. So i don't get lte but get excellent hspa+ speeds. I made a backup of v10f(used the unbricked guide) And i went back to that backup, no problem. Til i load back up it just shows one bar! No matter where i go in town it shows one bar in place i know i should have full bars! Then data is slow as well. So is there any solution for this? I want to go to ics cwm leak but i know that if gb is doing this the ics leak will probably do the same?
Solved went and did the unbrick method from the adb shell part. When i booted back to v10f att firmware i had full hspa and still had root!
I flashed the firmware for COI5 manually via odin and ever since then I cannot connect to LTE. Furthermore, I can barely connect to any signal. The bars show up, but it often takes a while for the 4G icon to show up. When it does, I am still not able to place a call, with Wi-Fi calling being the only hope I have to do so, but calls placed to me that way go straight to voicemail, so I have to call out from my phone.
Note: Knox is tripped, as I was rooted. I am also in an area where I alway get full bars of LTE, so location is not the issue.
Troubleshooting steps I have tried:
Reflashing COI5 firmware via odin.
Adding the LTE APN for T-Mobile.
Using Smart Switch to do emergency recovery.
Flashing BOH6 firmware (did not work as I don't believe you can downgrade firmware, was worth a shot anyways).
Flashing different custom ROMs (all repeated the same problem, which is how I narrowed it down to having to do with the firmware).
I am currently running completely stock at the moment. If anybody has any suggestions on what I should try next or how I can fix this, I would greatly appreciate it.
So the problem I'm having with my G3 is that the Network either drops and comes back repeatedly or completely drops and does not return. This only happens on 4G. When I go into network settings and change network mode to 3G it works fine and I get a constant signal all the time.
I have been using Fulmics ROM and I thought maybe that was the issue. But it wasn't.
I tried 3 different sims from three different carriers (Three, EE, O2) on several stock firmwares. (20N, 21C, 30A, 30F).
Each scenario is the same; network drops when phone is on 4G network mode, but its fine on 3G mode.
However, I have noticed that if I leave Wifi OFF allowing 4G data to connect first, then its fine. I can even turn Wifi ON again and the network is stable. I can even turn Wifi and Data OFF and the network is still stable.
But, if I toggle aeroplane mode, where Wifi connects first or where Wifi and Data is turned OFF; I am back to the network dropping.
Also, I live in London UK so there should not be any signal issues. Can anyone tell me why this is happening. I doubt it's software issue as I've tried several firmwares.
Any help is appreciated.
Mate I'm afraid there is a high possibility it's the Fulmics ROM.. I'm still trying to read up on the issue myslef, there's a ton of reports in the Fulmics thread and around.

I'm using an UK bought LG G3 as well (from Three) and started experiencing similiar issues after I flashed Fulmics. Even tried rolling back to 4.4.2 using a .tot file but didn't really help me.
Still scouring all around trying to find how to fix the issue..
engmia said:
Mate I'm afraid there is a high possibility it's the Fulmics ROM.. I'm still trying to read up on the issue myslef, there's a ton of reports in the Fulmics thread and around.

I'm using an UK bought LG G3 as well (from Three) and started experiencing similiar issues after I flashed Fulmics. Even tried rolling back to 4.4.2 using a .tot file but didn't really help me.
Still scouring all around trying to find how to fix the issue..
Click to expand...
Click to collapse
Hmmm looking back now this issue did start when I first installed fulmics 3.5. But shouldn't everything revert back to stock when you reinstall stock firmware.
thufz9585 said:
Hmmm looking back now this issue did start when I first installed fulmics 3.5. But shouldn't everything revert back to stock when you reinstall stock firmware.
Click to expand...
Click to collapse
That's what I thought but I guess it's a little bit more tricky.
Anyways I think I managed to restore some kind of stability in the signal, still unsure about the process though. Seems that different stuff are working for different people. In a few days I hope to have some information to give you how to fix it.
In the meantime try checking the Fulmics thread for ideas and suggestions (that's where I start off from).
engmia said:
That's what I thought but I guess it's a little bit more tricky.
Anyways I think I managed to restore some kind of stability in the signal, still unsure about the process though. Seems that different stuff are working for different people. In a few days I hope to have some information to give you how to fix it.
In the meantime try checking the Fulmics thread for ideas and suggestions (that's where I start off from).
Click to expand...
Click to collapse
Yeah let me know when you find a fix. Really appreciate the help.
One thing that is sort of a temporary fix for me, works on Three, EE and O2 (only ones i tried), is connecting Data first when on 4G mode.
So if I toggle airplane mode and if Wifi connects first then the network drops or keeps refreshing.
But, if I leave Wifi OFF and Data establishes a connection; the network is stable and I can then turn Wifi On again and the network will remain stable.
I just have to make sure the network does not lose connection (i.e. tunnel or airplane mode), and if it does ensure Data connects first.
Also, another thing. After I reinstalled Fulmic 5.3 it seems 4G mode is sort of stable. As in when on 4G mode instead of dropping the network it connects via 3G automatically. But this only happens with Three.
thufz9585 said:
Yeah let me know when you find a fix. Really appreciate the help.
One thing that is sort of a temporary fix for me, works on Three, EE and O2 (only ones i tried), is connecting Data first when on 4G mode.
So if I toggle airplane mode and if Wifi connects first then the network drops or keeps refreshing.
But, if I leave Wifi OFF and Data establishes a connection; the network is stable and I can then turn Wifi On again and the network will remain stable.
I just have to make sure the network does not lose connection (i.e. tunnel or airplane mode), and if it does ensure Data connects first.
Click to expand...
Click to collapse
Okay here is what worked for me - open this guide and download the Three specifiic Lollipop and Marshmallow .kdz files.
Flash the stock Marshmallow firmware first using the LG Flash Tool method. Your phone probably won't automatically get recognized since you're running Fulmics now so you'll need to change the COM port as described in post #
After that downgrade to stock Lollipop using the LGUP method. Personally I downloaded more updated (I think, not sure) files from here.
Then I proceeded to re-root and clean install Fulmics 5.1 and the 5.2 and 5.3 OTA updates from recovery. Booted and network works without drops now with 4G connectivity.
thufz9585 said:
Also, another thing. After I reinstalled Fulmic 5.3 it seems 4G mode is sort of stable. As in when on 4G mode instead of dropping the network it connects via 3G automatically. But this only happens with Three.
Click to expand...
Click to collapse
I changed my carrier and got an automatic SMS with configuration for my phone and instructions to save it. I should've known something was fishy when I recieved the "congratulations for setting up" message even before I recieved the actual settings. Anyways 4G was running fine on my new carrier with 32 mbps speed which is okay, much better compared to the same carrier 3G network, however I only had 3 bars of connection so I gussed what the heck, I should save that configuration after all, it might make things better. What a bloody mistake. I lost 4G connectivity and my phone refused to connect to the 4G network, only 3G (just as you describe).
What worked for me in this scenario was wiping the cache and dalvik (not really sure this step is even necessary to be honest, but I was headed for a full rom re-wipe anyway and decided to try with this first), going into the hidden menu and choosing LTE only connectivity (Fulmics Tweaks -> Hidden Menu [or the hidden code for the phone app if you decided to stay on stock, which I dont have] -> Modem Protocol -> RAT Selection -> LTE only. At this step my phone got to the usual 3 to 4 bars of connectiviy but was displaying "Emergency mode only" and no data at all. I proceeded to Settings -> Networks -> More -> Mobile Networks -> Access point names -> Reset to default from the menu. If network mode doesn't change back to GSM/WCDMA/LTE auto automatically, change it back manually. At this point I had restored back my 4G connection and everything is working normally (30-32 mbps connection stationary in my house through a wifi hotspot next to my laptop).
Good luck, I would follow the steps as described just in case. I tried many reflashes before that should've worked but didn't for me. However different things work for different people, hope this works for you and please report back
engmia said:
Okay here is what worked for me - open this guide and download the Three specifiic Lollipop and Marshmallow .kdz files.
Flash the stock Marshmallow firmware first using the LG Flash Tool method. Your phone probably won't automatically get recognized since you're running Fulmics now so you'll need to change the COM port as described in post #
After that downgrade to stock Lollipop using the LGUP method. Personally I downloaded more updated (I think, not sure) files from here.
Then I proceeded to re-root and clean install Fulmics 5.1 and the 5.2 and 5.3 OTA updates from recovery. Booted and network works without drops now with 4G connectivity.
Click to expand...
Click to collapse
I'd like to thank you so much for this information! I was having signal drop issue after installing Fulmics ROM. Tried to flash stock ROM but no success. After doing the downgrade via LGUP method to LP my phone is getting full signal again (at least I didn't notice any drop until now).
Thank you!
waltertakashi said:
I'd like to thank you so much for this information! I was having signal drop issue after installing Fulmics ROM. Tried to flash stock ROM but no success. After doing the downgrade via LGUP method to LP my phone is getting full signal again (at least I didn't notice any drop until now).
Thank you!
Click to expand...
Click to collapse
Glad I could be of help!
engmia said:
Okay here is what worked for me - open this guide and download the Three specifiic Lollipop and Marshmallow .kdz files.
Flash the stock Marshmallow firmware first using the LG Flash Tool method. Your phone probably won't automatically get recognized since you're running Fulmics now so you'll need to change the COM port as described in post #
After that downgrade to stock Lollipop using the LGUP method. Personally I downloaded more updated (I think, not sure) files from here.
Then I proceeded to re-root and clean install Fulmics 5.1 and the 5.2 and 5.3 OTA updates from recovery. Booted and network works without drops now with 4G connectivity.
Click to expand...
Click to collapse
Sorry for the late reply.
I followed your instructions and unfortunately it didn't work. :crying:
I first tried with the D85520f you provided and then with an updated D85521C firmware. But nothing worked.
The temporary fix, which I found works, is to ensure 4G mobile data establishes a connection first before Wifi (turn Wifi OFF then ON after data established). Then there is no signal drop until I go through a tunnel or phone restarts (signal drops completely), which means again i have to ensure 4G mobile data establishes a connection before Wifi or else it'll go back to the constant signal dropping.
Guess I'll just stick with 3G at all times. I've spent too much time trying to correct this than actually finding enjoyment in using the phone.
Anyway really appreciate the time and effort you took to help with this annoying situation. :good::good::good:
thufz9585 said:
Sorry for the late reply.
I followed your instructions and unfortunately it didn't work. :crying:
I first tried with the D85520f you provided and then with an updated D85521C firmware. But nothing worked.
The temporary fix, which I found works, is to ensure 4G mobile data establishes a connection first before Wifi (turn Wifi OFF then ON after data established). Then there is no signal drop until I go through a tunnel or phone restarts (signal drops completely), which means again i have to ensure 4G mobile data establishes a connection before Wifi or else it'll go back to the constant signal dropping.
Guess I'll just stick with 3G at all times. I've spent too much time trying to correct this than actually finding enjoyment in using the phone.
Anyway really appreciate the time and effort you took to help with this annoying situation. :good::good::good:
Click to expand...
Click to collapse
Modem 21C should be your answer! Please try with that.
Is anyone still out there
engmia said:
Modem 21C should be your answer! Please try with that.
Click to expand...
Click to collapse
I flashed dummies and get dropped 4g data like this.
I have tot back to stock and didn't help... not Kdz
Haven't downgraded yet to LP yet.
On turborom now.
Can I just flash this modem? Have a link to the 21c modem?
Flash in twrp or send via LG flash?
Some time ago, i updated my phone to 20h England via LGUP and i lost my H+ signal. The phone started to give only H (which is apprx. 8 Mbps speed). Before that I always had H+. Then i did factory reset, installed two different KDZ (which i used before). Yet, no H+ signal anymore. I deleted and reconfigured APN. Bu no chance... I tried my friends 4g sim card and it used 4g, but mine is a 3g+ sim card, so no 4g band for me. Do you know how to get H+ signal back? Shall i flash via TWRP, "system + boot + modem + bootloader" flashable zip files of 20A from http://forum.xda-developers.com/g4/development/stock-h815-20a-stock-images-kdz-t3232282 ? Can flashing modem zip file help? Do you have any advice?
bastab said:
Some time ago, i updated my phone to 20h England via LGUP and i lost my H+ signal. The phone started to give only H (which is apprx. 8 Mbps speed). Before that I always had H+. Then i did factory reset, installed two different KDZ (which i used before). Yet, no H+ signal anymore. I deleted and reconfigured APN. Bu no chance... I tried my friends 4g sim card and it used 4g, but mine is a 3g+ sim card, so no 4g band for me. Do you know how to get H+ signal back? Shall i flash via TWRP, "system + boot + modem + bootloader" flashable zip files of 20A from http://forum.xda-developers.com/g4/development/stock-h815-20a-stock-images-kdz-t3232282 ? Can flashing modem zip file help? Do you have any advice?
Click to expand...
Click to collapse
My lg g4 shows only H on 3g mode.I am getting upto 17mbps.
mine only gives 6-7 Mbps