[G4 General] steadfasterX:
FAQ

0) Is/will UsU be available for ARB 3 or higher?

no. never.

Reason:

UsU is based on an ARB 2 based aboot (part of the bootloader stack) and so any ARB > 2 will hard-hard brick your device if you would flash UsU on it.

(Hard-Hard brick means no way to recover other then sending for repair)

1) Is UsU reversible?

Yes and

no

.

Details: https://xdaforums.com/showpost.php?p=76444983&postcount=968

2a) So I can't flash any KDZ/TOT anymore?

2b) So I can't upgrade my STOCK ROM with the LG updater anymore?

Have you really read the limitations topic? I guess no.

You can't! At least for the KDZ flashing part: not yet.

SALT will allow flashing of KDZ files with the upcoming version 4.0 but until then do not flash with lgup and do not use the LG Android internal updater --> You WILL 100% brick your device.

Why? Read the above FAQ.

3) Will UsU void my guarantee?

Sure.

4) I have flashed UsU and now in Android settings and/or in fastboot it shows up as a LG LS991 - WHY?

The aboot mentioned in FAQ 1) is from a specific device: the ls991. Usually this is nothing which you need to care about. What you see in the Android settings is just parsed from the commandline (means from what aboot is telling) and has no further impacts of nothing. Its just a wrong named "variable" thats it. I still work on a fix to adjust this on boot to your real model but atm of writing it would require a kernel for each model just for this cosmetic thing..

As the UsU fastboot IS ls991 as written in FAQ #1 you will see it there and this is unchangeable - but nothing you need to care about.

5a) I flashed UsU and now the ROM bootloops

5b) I flashed UsU and now the ROM does not start

5c) I flashed UsU and now Android crashes with a blue/purple demigod screen

5d) I flashed UsU and now I have no SOUND and/or CAMERA anymore

5e) I flashed UsU and now I have no cell service anymore

Well there could be 3 reasons why this can happen:

- Either you have not flashed the baseband package in TWRP

- you try to boot a ROM which is not compatible with your model (check the GPT compatibility in SALT!)

- or you have a very sensitive (or strict..) device model

The first thing you should try is flashing the UsU kernel for your installed ROM.

If there is no UsU kernel for your ROM install a supported ROM and flash the UsU kernel afterwards.

If the problem persists or if you still want to use the unsupported ROM: flash the baseband package and the GPT compatibility is ok with the ROM you trying to flash.

If the problem persists:

1 )Try to flash the modem partition of your SALT backup before flashing UsU (nothing else!)

if the problem persists:

2) Some devices require to flash the full modem partition of Lollipop (instead of flashing the baseband package) in order to work after UsU has been flashed so if you are sure that you flashed the baseband package go here and download the modem or the KDZ file of a 10 (Lollipop) modem.img/modem.bin: codefire if you cant find what you need try that one: storagecow

Flash the modem file in fastboot mode like this:

fastboot flash modem modem.img

or in TWRP like this:

adb push modem.bin /tmp
adb shell
dd if=/tmp/modem.bin of=/dev/block/bootdevice/by-name/modem
sync
reboot

6) Is there a windows version to flash UsU?

No and there will be never one. Why? For this FWUL exists. Flash FWUL on an USB stick and boot from it. It's as easy as it sounds.

7) I want to use a custom ROM based on Android Nougat or Oreo. In the ROM OP they say I need the v29a/N bootloader stack. Is this true?

No. You will find in several ROM threads the hint that you must have a specific bootloader stack in order to make the ROM working properly.

What in reality is

needed

on these ROMs is just the MODEM (aka firmware) partition nothing else. Believe me I know this

for sure

;)

If you later want to install custom ROMs based on

N or O

(

any

model! and

any

ARB) --> N modem

1) Flash G4_29a_N_modem_UsU.zip in TWRP

2) Flash your baseband package (<model>_UsU_baseband_flash-in-twrp.zip) in TWRP again!! If you don't you will get bootloops, android hanging on boot or modem SoC crashes (blue demigod screen)

When you have a H815(!!!!) device with ARB = 0 you COULD flash the complete bootloader stack though (if you wish - but as said it is NOT needed. READ MY LIPS: IT IS NOT NEEDED but its possible though ):

UsU bootloader stack for N / O

8a) I flashed a KDZ with LGUp / LG Flashtools (you really hexedited a kdz/tot just to brick your device? cooool)

8b) I flashed the non-UsU (see FAQ 7 for the UsU one) v29a bootloader stack on my device

8c) I have no idea why but i bricked my phone (actually you have but you don't wanna tell)

You will need an external sdcard or something like the infinity dongle. In theory there is also the way to unbrick by QFIL but this way is incredible dangerous if you use the wrong files (read FAQ #23!!). The external sdcard method will work only when your device is detected in 9008/QDL mode. If you connect your device to the PC and see nothing (Windows: device manager, Linux/FWUL: open a terminal and type: lsusb) then this guide will not work for you. The only chance is to use e.g. infinity or QFIL but there is no QFIL guide out there I would trust..

For the external sdcard unbrick read and follow the sdcard unbrick guide.

It is important that you know which bootloader stack you had on your device (in terms of ARB)

The only difference for UsU devices is that you need to flash:

the aboot_UsU.img to the aboot partition, the laf_UsU.img to the laf partition and the rawres_UsU.img to the raw_resources partition:

fastboot flash aboot aboot_UsU.img
fastboot flash laf laf_UsU.img
fastboot flash raw_resources rawres_UsU.img

9a) Will UsU work for my model?

Yes (h818 has been disabled though)

9b) Will UsU work for my country/region?

UsU has no restriction on a specific G4 model or country version.

9c) Will UsU work for any ARB?

UsU will work on ARB 0, 1 and 2 ONLY and you will need LP or MM to be able to actually flash UsU.

Again flashing UsU is a risk always. It happens on your

own responsibility

!

10a) Will UsU allow me to flash TWRP?

Yes.

10b) Will UsU allow me to flash stock ROMs?

Yes. You will be able to flash stock LP, MM, N

10c) Will UsU allow me to flash custom ROMs?

Yes. You will be able to flash any custom ROM of your choice (any android version)

10d) Will UsU allow me to root my device?

Yes. Ofc you can root with magisk as usual.

11) I follow your PoC thread since the beginning.. So UsU has no limitations regarding cell service/signal anymore?

Everything should work (cell service, mobile data, wifi, BT, call, sms, etc). UsU will not replace the complete bootloader stack as it was done in the early implementations.

By keeping your real bootloader stack the hardware like camera, modem / baseband can be initialized as it should and so no limitations are known (yet).

Again flashing an unofficial unlock is always a risk. Do not blame me when something is not working as it should.

You do this on your own responsibility

12) I want to flash a custom ROM but there is none for my model available what now?

SALT will show a field named GPT compatibility. Just flash a ROM which is compatible with your device. Thats it.

Read more about the compat check in SALT in the SALT FAQ #15.

13) I want to flash a custom ROM but it says "This ROM is for device xxxx but this device is >.< !! You told that I can flash any ROM so whats wrong here?

I wrote it in the LIMITATIONS/KNOWN ISSUES topic of the OP but here again:

Taken from the OP:

Here a guide by @sdembiske https://xdaforums.com/showpost.php?p=76405252&postcount=947

14) I have unlocked with UsU and all went fine. I flashed a ROM and it bootloops and now my phone died!! What have you done with my device? It never had this issue before in the last years!?

Unfortunately this is not UsU's fault. It's yours. Or better its LGs. The g4 is known to have faulty mainboard and when you boot a fresh flashed ROM this is very heavy cpu intensive and so can cause the ILAPO which means the hardware fault occurs. Yes it has not happened to you in the past but how often did you flashed a new ROM in the past? Ask LG for a mainboard replacement (yes even when out of guarantee) or check the bootloop fix it list : https://bit.do/ilapofixg4

15) I flashed the LP modem, but now it wont let me get past lockscreen. Do I need to factory reset?

background info: the modem partition contains decrypt parts so the screenlock may fail to decrypt.

Doing a factory reset is one option which will fix this.

If you dont want to loose your data reset just the password of the screen lock:

https://xdaforums.com/android/software-hacking/remove-lockscreen-recovery-t3530008

16) I just wanna flash Nougat STOCK. Are there any worry free UsU downloads for it available?

Sure: here

After flashing ensure you flash your model baseband package!

After that and while still in TWRP: Choose Reboot -> RECOVERY ! This should ensure TWRP will not be overwritten on Android boot

17) What is the recommended way to backup with TWRP?

ONE/FIRST TIME backup.

Do this just

ONCE

--> Select these partitions to backup:

- Firmware_Image
- EFS
- BL unlock state
- Bootloader
- Carrier

USUAL/DAILY BACKUP

(e.g. to test other ROMs, before an upgrade, etc) --> Select these partitions to backup:

- Boot
- Recovery
- System
- Data
- Encryption metadata -> when your device is encrypted ONLY
- Firmware_Image

18) I have flashed the bootloader stack of N on my non-H815 device and now I have issues (no cell service, no bluetooth etc)

There could be 2 reasons why: Either you haven't read the OP guide properly and flashed the bootloader stack or you were one of the "early birds" flashed the full ROM which includes the Nougat bootloader stack.

H815-ONLY_ARB-0_29a_bootloader_UsU.zip (formerly named: G4_ARB-0_29a_bootloader_UsU.zip)

H815-ONLY_ARB-0_v29a_FULL-STOCK-ROM_UsU.zip (formerly named: G4_ARB-0_v29a_FULL-STOCK-ROM_UsU.zip)

The guide in the OP told you to do a SALT backup before flashing UsU.

If you have followed the guide properly you should have it and the above is one of the reasons why I said its required to do it.

( If you lost your backup there is still a way you can go: Follow FAQ

#20

)

Open a terminal in the directory where you SALT backup before flashing UsU (or your extracted KDZ) is.

Then put your device in fastboot mode and type these commands:

fastboot flash factory factory.bin
fastboot flash hyp hyp.bin
fastboot flash modem modem.bin
fastboot flash pmic pmic.bin
fastboot flash rpm rpm.bin
fastboot flash sbl1 sbl1.bin
fastboot flash sdi sdi.bin
fastboot flash sec sec.bin
fastboot flash tz tz.bin

Read the output of the flashing on the screen and in your terminal. Do NOT flash anything else! Just the above - but ALL of the above! (if you miss a single file you

will

HARD BRICK)

If something is failing do

NOT

continue and try to re-do the above commands. if it still fails write in this thread or better come into IRC (when between Monday and Friday)!

If something failing here it WILL

brick

your phone.

19) I have flashed UsU but now I always see a secure boot error text at the top of my screen when booting (TWRP, Android, download and fastboot mode). Is it possible to remove that?

Really? I mean REALLY? Its clearly written in the OP - CHANGES IN BEHAVIOR !

20a)I have flashed UsU and now I want to downgrade/upgrade my bootloader stack. How?

20b)You were on LP or older MM firmware when you have flashed UsU and now having issues? -> Upgrade your bootloader to MM! Read here how:

Download a KDZ of

your

device model.

Keep in mind that there are frankenstein devices out there (means refurbished devices with mixed hardware inside so you think u have model XXX as it was shown in Android but the mainboard is NOT the same!).

How to identify a Frankenstein device? Read FAQ

#21

.

IMPORTANT: Check the ARB of that KDZ (SALT will show the ARB of a KDZ on extract!) - If you are unsure - DO NOT PROCEED. you can easily hard brick your device if!

Extract that KDZ with SALT - DO

NOT

USE ANY OTHER TOOL FOR EXTRACTING! The known windows tools like LG Firmware extract does not extract what we need here and not in the way we need it! So do not use that! You have been warned..

Open a terminal in the directory where you SALT backup before flashing UsU (or your extracted KDZ) is.

Then put your device in fastboot mode and type these commands (you have another file extension? read FAQ #24):

fastboot flash factory factory.bin
fastboot flash hyp hyp.bin
fastboot flash modem modem.bin
fastboot flash pmic pmic.bin
fastboot flash rpm rpm.bin
fastboot flash sbl1 sbl1.bin
fastboot flash sdi sdi.bin
fastboot flash sec sec.bin
fastboot flash tz tz.bin

Alternative

with TWRP (if the above fastboot cmds work for you

no

need to do this!):

Boot TWRP
adb push factory.bin /tmp/
adb push hyp.bin /tmp/
adb push modem.bin /tmp/
adb push pmic.bin /tmp/
adb push rpm.bin /tmp/
adb push sbl1.bin /tmp/
adb push sdi.bin /tmp/
adb push sec.bin /tmp/
adb push tz.bin /tmp/
adb shell sync
adb shell "dd if=/tmp/factory.bin of=/dev/block/bootdevice/by-name/factory"
adb shell "dd if=/tmp/modem.bin of=/dev/block/bootdevice/by-name/modem"
adb shell "dd if=/tmp/hyp.bin of=/dev/block/bootdevice/by-name/hyp"
adb shell "dd if=/tmp/pmic.bin of=/dev/block/bootdevice/by-name/pmic"
adb shell "dd if=/tmp/rpm.bin of=/dev/block/bootdevice/by-name/rpm"
adb shell "dd if=/tmp/sbl1.bin of=/dev/block/bootdevice/by-name/sbl1"
adb shell "dd if=/tmp/sdi.bin of=/dev/block/bootdevice/by-name/sdi"
adb shell "dd if=/tmp/sec.bin of=/dev/block/bootdevice/by-name/sec"
adb shell "dd if=/tmp/tz.bin of=/dev/block/bootdevice/by-name/tz"

Download this verify tool to ensure the flashing was successful: [ATTACH]4687157[/ATTACH] ([URL="http://leech.binbash.it:8008/misc/verifyflash.zip"]mirror --> verifyflash.zip[/URL])

Usage:
extract verifyflash.zip
adb push verifyflash.sh /tmp/
adb shell chmod 755 /tmp/verifyflash.sh
adb shell /tmp/verifyflash.sh

Read the output of the flashing on the screen and in your terminal. Do NOT flash anything else! Just the above - but

ALL

of the above! (if you miss a single file you

will

HARD BRICK)

If something is failing do

NOT

continue and try to re-do the above commands. if it still fails write in this thread or better come into IRC (when between Monday and Friday)!

If something failing here it WILL

brick

your phone.

21)What is a frankenstein device and how can I identify if I have one?

A so called Frankenstein device shows up different in Android then it is in hardware.

Often happens on "refurbished" devices and almost everything you can buy on AliExpress is one.

The

only

way to identify your REAL model is by disassembling the device.

No

there is NO other way. Everything else can be tricked by software.

Follow the guide here: https://www.ifixit.com/Guide/LG+G4+Motherboard+Replacement/51202

now you are able to see the

REAL

model printed on the front of your mainboard.

Is a Frankenstein bad? Hell yes. Can you live with one? Up to you. Technically there are good chances that it work as it should - especially when UsU'ing it.

Main problem here is that some stupid ppl out there take a board (often a h810 or h812 but there is no restriction) and flash a different PBL (primary boot loader) on it to load what they like to load. usually they flash h815 ROMs as that is best for selling as it can be unlocked officially (which NEVER works - as the IMEI and/or serial will never list a Frankenstein as a h815).

So actually it is not 100% clear what they did with your phone EXACTLY - and that leaves room for bricks when flashing stuff - or even worse: you might encounter partly not working stuff. In most of the Frankensteins I saw they work good when you flash the real models ROMs, bootloader stacks and modem partitions but well there is no guarantee for nothing here!

Other then that you can use SALT (part of mAid) to determine your model. This with the ARB shown gives you a 80 -90 % clue of your real device model.

E.g. when you bought a h815 (which is known to NEVER EVER have an ARB higher then 0) and it shows h810 in SALT then you can be 100% sure that it is not a h815 and 90% sure that it is the model shown in SALT instead.

22)I have a H812 and having issues after flashing the N stock ROM / AOSCP Nougat. What can I do?

Walk throughs:

Stock N report: https://xdaforums.com/showpost.php?p=75913373&postcount=12 by user @grantdb (consider to show ur appreciation by clicking thx on that post)

AOSCP N report: https://xdaforums.com/showpost.php?p=75890188&postcount=361 by user @sdembiske (consider to show ur appreciation by clicking thx on that post)

LineageOS O report: https://xdaforums.com/showpost.php?p=76799406&postcount=1100 by user @sdembiske (consider to show ur appreciation by clicking thx on that post)

23)uhm I wanna / I have flashed with QFIL...

I wrote millions of times that using qfil is f*** dangerous and shouldn't be used.

The process of using QFIL with the wrong files can CONVERT your device or blow fuses! Never ever use qfil unless you REALLY understand what files you flash:

This requires to analyze the files (hexedit) you trying to flash with qfil. which is something 99% of the average user CAN'T.

Which means: do not use it unless you don't care about damaging your device ofc..

The only less-dangerous way is of unbricking from the 9008/QDL mode by my sdcard unbrick method but when you already used qfil you may have damaged your device already.

If you UsU'd your device there is even one more reason to NOT use qfil!

As said you shouldn't use qfil

anyways

but when you UsU'd your device it's even

more

important.

WHY I say using QFIL is evil?

Especially on devices which have no ARB >2 firmwares (like h812, h815, h818, h819 and F500) using QFIL is the worst idea you can have.

Just to be crystal clear: if you have UsU'd or not --> that doesn't matters!

QFIL is dangerous because:

some files you can find around will increase your ARB !

Increasing your ARB means you can never flash your original bootloader stack anymore (on devices having no ARB >2 firmwares)

If you can not flash your original bootloader stack anymore you can not load parts of the modem partition.

If you can not load these parts of the modem partitition you can not get any cell service - full stop. Yes here it ends. You can't go back and so you are stuck with like it is.

Well you can still go back by:

- replacing the mainboard

- replacing the cpu/whatever chip on the mainboard

There is ONE single exception to the above: If you have (still) a "nonfusing" device. Nonfusing devices may be able to flash any ARB but beware:

I had a nonfusing device which suddenly changed somewhen during my UsU hacking sessions.

I have one user who was able to flash a lower ARB then he had before because his device was stated as a nonfusing device. There is no guarantee but it is a chance for you.

Read more about the ARB background here: https://bit.do/unlockg4

24)I have a partition file with the extension: [ bin | image | img | mbn ]. How can I convert this?

The extension is not important. The way how you extract files - is. That's why I say all the time use SALT.

On Windows the file extension matters a lot which is

not

the case for Linux/Android.

There is no need to convert anything as they all are just raw image files.

25a)I have UsU'd but now in TWRP it does not show my model. Instead something like Chinese or strange characters.. How can I solve this?

25b)I have UsU'd but something went wrong while flashing..! I can still turn on the phone and I see the secure boot error.. What now?

25c)I have UsU'd but I cannot open the download mode anymore.. What now?

This can happen when you tried to flash UsU with a completely outdated version of SALT or using an unsupported version of FWUL (like using it in KVM, VMware ,..).

Ok how to fix this now?

Boot to fastboot mode.

Extract the UsU unlock zip file of your model.

Flash the following from that zip file:

fastboot flash raw_resources rawres_UsU.img
fastboot flash laf laf_UsU.img

That's it. TWRP will detect the model now correctly. If not share the TWRP log as described in the TWRP(!) thread FAQ 4a.

26a)How can I identify my bootloader stack from my backup files?

26b)How can I identify my current installed bootloader stack?

26a)

To find out which exact firmware version you had installed before UsU'd can be done easily when you have a backup (which you should have).

So to grab that info from your backup (requires Linux/FWUL):

Open a terminal in the directory where you have your SALT backup before UsU'd.

Then:

strings misc.bin | grep LG

It should display a long string containing your model name and the exact firmware version

26b)

There is no easy way atm for this. It is MUCH easier to just flash the newest bootloader stack like described in FAQ #20 in this post.

.. but if you really want something to start with:

a) do a SALT backup (basic)

b) extract sbl1 of any(!) KDZ files you can find for your model (you see now what a bad idea that is?)

c) do a md5sum on sbl1.img/bin (both: on your backup and the KDZ one) and compare. Once you have found a match you know the version.

27) a) What is the "bootloader stack" on the G4?

27) b) What is the boot process on a Qualcomm device like the G4?

The bootloader stack is a set of partitions (and optionally a partition table) which MUST be on the exact same firmware and ARB level.

There are exceptions to this but you really wanna risk a brick?

Keep the bootloader stack files together otherwise you will brick your device.

Why is explained in the following topic.

The LG G4's bootloader stack partitions are:

tz (Qualcomm Trust Zone. It performs low-level operations, including working with QFuses (rpmb secured mmc partition))

sbl1 (secondary bootloader)

sdi (trust zone storage partition. The data which is used by Trust Zone)

pmic (power management integrated circuit - related to rpm)

rpm (Resource and Power Manager firmware. Firmware for specialized SoC, responsible for resources and power)

aboot (<--- replaced by UsU ! so NEVER touch this again after UsU'ing) - Android boot, little kernel, lk, fastboot mode

hyp (Hypervisor - Virtual Machine Monitor, related to tz in order to protect the device/kernel - afaik)

Special partitions (

NOT

part of the bootloader stack - but either related, optional or as for the PBL - informative):

The following do not directly belongs to the above stack but it is related. You will never touch PBL, laf or raw_resources and the rest are optional ones.

PBL - Built-in ROM Qualcomm primary boot loader (

read-only

)

laf (download mode - can be anything on unlocked / UsU'd devices but for locked devices it MUST match the bootloader stack)

raw_resources - contains boot messages read by aboot. Examples: LG logo, bootloader has been unlocked warnings

recovery (recovery mode - can be anything on unlocked / UsU'd devices but for locked devices it MUST match the bootloader stack)

modem - hardware firmware (sound, baseband, camera, video, ...) accessed and loaded by rpm and Android (kernel, Android) - must STILL match the device's ARB of the bootloader! Otherwise those files cannot be read/loaded (most of them are signed so certificate protected!)

The boot process on a qualcomm device is as follows:

All of these partitions are signed by a certificate chain which starts in the PBL (which is read-only so cannot be altered - easily)

pbl  verifies and boots: sbl1 partition

sbl1 verifies and boots: tz, then: aboot

aboot verifies the next boot stage (boot / recovery / laf partition):

-> for locked devices: enforce verification result (so decline boot when failed)

-> for unlocked or UsU'd devices: print just a warning (so continue when failed)

For a graphical view: https://lineageos.org/engineering/Qualcomm-Firmware/ (G4 is: "2013-2016 Era")

28)a) I want STOCK - how can I revert back once I flashed a custom ROM?

28)b) how can I flash another version of any STOCK rom for my model?

for Nougat:

FAQ #16

for any other:

extract with SALT system + boot + modem partition of the stock ROM kdz of your choice

(beware of the ARB!!! SALT will tell you on extracting the ARB and in the main window your device's ARB. do not flash anything higher then what the SALT main screen is showing or you might have a paperweight afterwards!!!! yes, even the system image can blow fuses!)

flash them in fastboot:

fastboot flash boot boot.img
fastboot flash system system.img
fastboot flash modem modem.img

boot TWRP (if you do not get into TWRP at the first try it gets overwritten. if that happens you must re-flash TWRP in fastboot)

flash the baseband package of your model

factory reset in TWRP (obviously all your data will be lost - so backup before)

if you encounter issues FORMAT data in TWRP (obviously all your data will be lost - so backup before)

29) I have a h810 and an ARB of 3 or higher. I heard there is a way to unlock this specific model somehow?! Is that true? If so how??

UsU will only work up to and including ARB 2 but the h810 is special as it turns out that its PBL (primary bootloader) SEEMS to be compatible with the h811.

There are 2 users reported that it worked for them but again this is EXTREMELY risky - especially on Frankensteins (i.e. refurbished models) !!!

I cannot guide you on that but check out my answer here: https://xdaforums.com/showpost.php?p=80056484&postcount=1857

30) Video framerates are low(er) with UsU?

As mentioned in the OP above the video framerates might be lowered after flashing UsU.

This is due to the fact that the required files for high performance video will not load properly anymore and so must be replaced.

Replacing those firmware files is a risk and as it is working ok enough for the most users that patch will not be included in any ROM.

If you really think you need this patched ensure you read the instructions here thoroughly and understand them 100% before proceeding to apply it: G4-VideoLag-Fix

ZZZ) I have a problem / question not listed here. What should I do?

All known issues are either fixed or listed above but ofc it can happen that you find something which is not listed here and you want to report it.

The very first thing you have to do is:

Open TWRP

Choose the Wipe menu

Choose FORMAT DATA (not a factory reset!)

Test if your problem is gone

ATTENTION:

This will

completely

clean your internal storage - all pictures etc everything will be lost so ensure you have a backup!

HINT: TWRP will

not

save your internal storage in a backup (read here why) so you have to take care

otherwise

!