[ONE Q&A, Help & Troubleshooting] Negan:
Oneplus Bricklooping, Never ending Audio FX FC error, No IMEI/Baseband unknown, Corrupt EFS

READ THIS!!! ​

I cannot guarantee that this will work for everyone. However It has proven to be a solution for almost everyone that have used it. So if it does not work I ask that you be respectful in posting as such. Keep in mind that I myself am not having this issue. I was however compelled to try to help you guys, my fellow user. My hope is that I have given you a second chance. If it does work please be more careful!!!

Ok guys so I've read a lot of posts that say some of you guys are experiencing the above problems, and have tried what seems like everything to fix your baby. I've read the "flash color os" fix which seems to work for some but not all.

So I myself do not have this issue but a buddy of mine did so I was really wanted to not only help him fix his baby, but also anyone out here who is experiencing this issue.

Please note that if you have twrp installed you can skip down to "part 2" and simply run the command in terminal command via twrp

I am making a package for you to download which contains all files needed to make this happen.

Please note the methods here are not for fixing issues resulting from flashing various zips associated with any lollipop Roms or mods, nor is this thread a support thread for such problems

So inside it you will have a few files:

persist.img

reserve4.img (update: this file is not needed so ignore it!)

cm-11.0-XNPH30O-bacon-signed-fastboot_64GB.zip

adb-setup- 1.3.exe

please note that any commands run in fastboot mode require you to have an unlocked boot loader. If you are not sure if you are unlocked then that means you aren't! So to do so put the device in fastboot mode and type: "fastboot oem unlock"

Update: you don't need to worry about the reserve4.img or the 30O zip. if you have no O.S. then you can flash the 30O but we now know all that is needed is to flash the persist.img

INSTRUCTIONS:

EXTRACT ZIP

IF YOU HAVEN'T INSTALLED ADB/FASTBOOT DRIVERS RUN THE adb-setup- 1.3.exe FILE TO INSTALL ADB SYSTEM WIDE

IF YOU ALREADY HAVE ADB INSTALLED SKIP THAT STEP

OPEN A CMD WINDOW WHEREVER YOU HAVE THESE FILES EXTRACTED

TYPE THE FOLLOWING COMMANDS IN YOUR CMD WINDOW WITH DEVICE IN FASTBOOT MODE:

fastboot erase persist

fastboot flash persist persist.img

now reboot and check if all is working. If you have no O.S. installed then you will need to flash something to get back up in running: see below

Note that this will wipe your device 100% so if anything is on your phone back it up to your PC!

This next part (in green text) is only if you have no os installed and not necessary for most people:

[*]WE ARE NOW GOING TO FLASH 30O AND THEN ALL SHOULD BE FORGIVEN

[*]SO EXTRACT THE cm-11.0-XNPH30O-bacon-signed-fastboot_64GB.zip

[*]RUN THE flash-all.bat FILE FROM FASTBOOT AND YOU SHOULD BE CURED!!!

[*] Please note that some users may get an error from running the flash-all.bat/.sh

If so simply extract the .zip and flash all manually and you will get the desired result.

Part 2

If for some reason you have relocked your bootloader and still have twrp ( you'll know if its locked if you flash these images and it says "failed, device not unlocked"

So in this case reboot to twrp and run a terminal command with the following exactly as written

make_ext4fs /dev/block/mmcblk0p15

Then reboot and you should be all set!

Below are two different files for you to use. the first one contains the persist.img . I am uploading it seperate for those of you who already have a copy of 30O. I see no need in making you wait longer to dl this if you already have 30O.

I am uploading the full package which contains everything for those who need it all

If you found this helpful all I ask is you hit the thanks button!

Downloads ↓

NEVER SETTLE!

Full Package

If you are unable to use fastboot for whatever reason check this post for a flashable zip via custom recovery http://xdaforums.com/showthread.php?p=55981898

Big shout out to my buddy AddisG for testing and confirming this works! We've been working on this for a long time and it's finally paid off

Also thanks to [MENTION=5427631]Vonnegut[/MENTION] for helping me maintain this thread and providing valuable information

Now once you are up and running again it's a good idea to not only backup your efs, but also copy that backup to your pc/cloud.

To do so is very easy. You'll need the app "terminal emulator" or alternatively you can do this on your Linux box too!

Issue the following commands to back them up:

open terminal

su

dd if=/dev/block/mmcblk0p10 of=/sdcard/modemst1.bin bs=512

dd if=/dev/block/mmcblk0p11 of=/sdcard/modemst2.bin bs=512

That will create two efs backups on your sd card. Make sure you copy them somewhere. DO NOT FORGET!!!

Now to restore your efs simply enter fastboot mode and flash the two efs files you backed up.

the commands are:

fastboot flash modemst1 modemst1.bin

fastboot flash modemst2 modemst2.bin

If you've tried all of the above and still have no baseband you can try this:

fastboot erase modemst1

fastboot erase modemst2

Please report if this works for you!!!

I sure hope it does!!!