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[PSA] **WARNING** DO NOT TRY TO DOWNGRADE YOUR G4 BOOTSTACK (in USA at least)

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waylo

Senior Member
May 9, 2010
1,669
489
This was not written anywhere specifically on the LG G4 forums that I could find. But every flash-addict needs to be warned. It is something you want to know before you continue tinkering.

Several users (myself included) have made the unfortunate mistake of attempting to downgrade their bootstack (for various reasons) to a former version.

DO NOT DO THIS (at least for the USA T-Mobile H811 version, and possibly other USA versions, per @autoprime)! It will result in a hard brick! Specifically, this results in the "Qualcomm QDLoader HS-USB port ( 9008 )" error. Connecting your phone to a PC will pop up with this active connection, but nothing else. There is no download mode. There is no publicly available fix as of yet.

This WILL happen both through KDZ restore as well as flashing bootstack .zips.

Yes, an official KDZ image can BRICK your USA phone, if you try to rollback.

This is in stark contrast to other manufacturers (i.e. Samsung), where the attempt to flash an older bootloader/modem/radio will simply fail, but your phone is not bricked.

I have conferred with @autoprime, who confirmed that with each OTA firmware release (on T-Mobile it was 10H, and now 10N), the version # increments. Flashing a lower version # will result in brick.

I have searched far and wide for a DIY fix. Without the proper firmwares in the right format, as well as the right flashing software, your phone is done and must be sent in for LG repair.

To check what antiroll-back version you are on, input this sequence in the dialer (T-Mobile and ATT) and scroll down:
*#*#244773825625#*#*

Flashing a bootstack version less than this # (through KDZ or zip) will brick the phone. You are free to flash anything equal or higher than the version listed.

EDIT:
The 20i MM update for the H811 is v2 antirollback. The 10n bootstack is also v2. So flashing between the 2 (returning from MM to Lollipop) should not hard brick the phone.

EDIT 2:
The 20o MM update is v3 antirollback. Once you go 20o, you cannot go back.

For your flashing needs, I suggest you use LGUP and NOT LGFLASH, as LGFLASH will ignore the rollback flag and brick your phone without remorse!
 
Last edited:

autoprime

Recognized Dev / Inactive Recognized Contributor
Jun 23, 2010
2,638
11,898
thanks for the thread @waylo

I have checked the most recent international builds and all are still on "v0". Tho that could always change in the future... but as of today... "v0"

The original out of box Tmo h811 version was "v0"... after the first forced OTA it became "v1"... as of 10N it is now "v2".
I do not have access to the latest AT&T, Sprint, US Cellular or Verizon bootstacks (seems there are no new KDZ's for them and no one has dumped the files) so I cannot confirm if AT&T, Sprint, US Cellular or Verizon's latest OTAs also move it up to "v2" or if still on "v1".

Actually.. I'm not even sure if Sprint, US Cellular or Verizon got a 2nd OTA yet.. but I know AT&T has "10i". If any 10i users who are rooted could dump the bootstack for me and send it over I can confirm.

Latest I know of for Sprint is ZV5.. thats "v1". US Cellular.. not sure.. but 10C was "v1". Verizon... again.. not sure what latest is.. but 11A is "v1".

*edit*
just checked US991 10D... still "v1".
 
Last edited:

Sj12345

Senior Member
May 22, 2012
346
203
Bakersfield
thanks for the thread @waylo

I have checked the most recent international builds and all are still on "v0". Tho that could always change in the future... but as of today... "v0"

The original out of box Tmo h811 version was "v0"... after the first forced OTA it became "v1"... as of 10N it is now "v2".
I do not have access to the latest AT&T, Sprint, US Cellular or Verizon bootstacks (seems there are no new KDZ's for them and no one has dumped the files) so I cannot confirm if AT&T, Sprint, US Cellular or Verizon's latest OTAs also move it up to "v2" or if still on "v1".

Actually.. I'm not even sure if Sprint, US Cellular or Verizon got a 2nd OTA yet.. but I know AT&T has "10i". If any 10i users who are rooted could dump the bootstack for me and send it over I can confirm.

Latest I know of for Sprint is ZV5.. thats "v1". US Cellular.. not sure.. but 10C was "v1". Verizon... again.. not sure what latest is.. but 11A is "v1".

can you share the method to know if the bootstacks change with each ota?
I am pretty sure ATT has anti rollback on!
or give me the code for dump the bootstack
 
Last edited:
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waylo

Senior Member
May 9, 2010
1,669
489
This is probable because of the huge security flaw in older versions...they probably dont want anyone returning to a vulnerable state...stagefright was a nasty flaw and i think moving forward we will be able to roll back to what we have now

That's a nice thought, but it will not be borne out until the next OTA comes out and we check the version. I wouldn't recommend you act on this supposition unless you have the time for a repair and a backup phone.
 

jamesd1085

Senior Member
Dec 6, 2012
929
465
Newark
That's a nice thought, but it will not be borne out until the next OTA comes out and we check the version. I wouldn't recommend you act on this supposition unless you have the time for a repair and a backup phone.

It was just a shot in the dark...but i always read and am very careful what i flash...but on the other hand my best friend has a good bit of experience with Android repair and a very pricey computer and a rather nice jtag device...I'm just hoping lg isn't turning the way of Samsung and trying to block out development as it will be the reason if i ever leave lg devices...locking out development is a boner killer and i wont think twice but to move to more open oems...lol
 

tabp0le

Inactive Recognized Developer
Oct 4, 2013
1,824
3,561
Phoenix
www.spryservers.net
thanks for the thread @waylo

I have checked the most recent international builds and all are still on "v0". Tho that could always change in the future... but as of today... "v0"

The original out of box Tmo h811 version was "v0"... after the first forced OTA it became "v1"... as of 10N it is now "v2".
I do not have access to the latest AT&T, Sprint, US Cellular or Verizon bootstacks (seems there are no new KDZ's for them and no one has dumped the files) so I cannot confirm if AT&T, Sprint, US Cellular or Verizon's latest OTAs also move it up to "v2" or if still on "v1".

Actually.. I'm not even sure if Sprint, US Cellular or Verizon got a 2nd OTA yet.. but I know AT&T has "10i". If any 10i users who are rooted could dump the bootstack for me and send it over I can confirm.

Latest I know of for Sprint is ZV5.. thats "v1". US Cellular.. not sure.. but 10C was "v1". Verizon... again.. not sure what latest is.. but 11A is "v1".

*edit*
just checked US991 10D... still "v1".

Does this also apply to TOT files? Say we upgrade to ZV6 when it comes out. Can we use a TOT file to flash to ZV5?
 

waylo

Senior Member
May 9, 2010
1,669
489
Does this also apply to TOT files? Say we upgrade to ZV6 when it comes out. Can we use a TOT file to flash to ZV5?

Anything that will attempt to rewrite the bootstack will cause this. So if the TOT file includes recovery + bootstack + system (I'm guessing it does if it behaves like a KDZ), it will have the same implications.
 

Agimax

Senior Member
Nov 17, 2009
1,211
1,252
Indianapolis
Well, for the G2 & G3, we had a fairly easy way to still fix the 9008 mode, i had even fixed my G2 that had those gazillion partitions show up in Linux (after shorting the chip pins). Maybe something like this can be done for the G4, especially if we output all of the G4's partitions from a working variant and then DD them back to the proper partitions.

For example this was for the G3
http://forum.xda-developers.com/lg-g3/general/unbrick-lg-g3-qhsusbbulk-qualcomm-9008-t3072091
 

waylo

Senior Member
May 9, 2010
1,669
489
Well, for the G2 & G3, we had a fairly easy way to still fix the 9008 mode, i had even fixed my G2 that had those gazillion partitions show up in Linux (after shorting the chip pins). Maybe something like this can be done for the G4, especially if we output all of the G4's partitions from a working variant and then DD them back to the proper partitions.

For example this was for the G3
http://forum.xda-developers.com/lg-g3/general/unbrick-lg-g3-qhsusbbulk-qualcomm-9008-t3072091

I looked through all of that earlier, and those fixes sure made the G2 + G3 near-bulletproof recoverable phones. I'm sure a fix for the G4 would be similar as it's the same USB connection that's kept alive despite bricking.

Specifically for the G3 example, right now we're missing ALL required parts:
1. No TOT files available (actually just looking, Sprint is the only one). Can't convert KDZ to TOT as far as I could find.
2. Equally if not more important, no G4 chip setting available in the existing Board diag utility.
 
Last edited:

Barsky

Senior Member
Aug 23, 2010
1,346
201
MintMobile
Well, as OP knows, I did this to mine. Its current status is Received at LG support. So now I nervously wait to find out if it is repairable (has to be). Their form letter doesn't make you feel comfortable, either :)

[FONT=&quot]Warranty Repair Notice:[/FONT][FONT=&quot] [/FONT]

  • [FONT=&quot]The device warranty does not cover physical, liquid, or cosmetic damage. If the device is damaged and deemed repairable charges may apply.[/FONT]
  • [FONT=&quot]If the device is deemed as un-repairable, the device will be returned to you as is.[/FONT]
  • [FONT=&quot]Charges may apply for units that are out of warranty by manufacturer‘s date code.[/FONT]
But when I needed the sim slot in my G3 replaced, I also received this email and a few days later, had my phone back in my hands all nicely repaired.
 

Sj12345

Senior Member
May 22, 2012
346
203
Bakersfield
@waylo, @autoprime .... when you say antirollback, do you mean this???
d23047efd05e42272c7434a7d2652c02.jpg
 
Last edited:
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autoprime

Recognized Dev / Inactive Recognized Contributor
Jun 23, 2010
2,638
11,898
@waylo, @autoprime .... when you say antirollback, do you mean this???
d23047efd05e42272c7434a7d2652c02.jpg

ooh fancy! im not sure if g4 has that displayed in the settings > about screen.. but maybe? it's not on mine tho (H815 10C)

But yes.. that would be what's being referred to in this thread. As your screen shows "1"... so any bootloader's at "v0" would brick phone... while any "v1" or higher" would work. and if you were to flash a "v2" bootloader.. the versioning would be updated and you could no longer flash anything under "v2".. etc etc.

I'd love to hear from other G4 users if they have this menu value on their phones... would make it easier on me to know which updates are at which version.
 

Sj12345

Senior Member
May 22, 2012
346
203
Bakersfield
ooh fancy! im not sure if g4 has that displayed in the settings > about screen.. but maybe? it's not on mine tho (H815 10C)

But yes.. that would be what's being referred to in this thread. As your screen shows "1"... so any bootloader's at "v0" would brick phone... while any "v1" or higher" would work. and if you were to flash a "v2" bootloader.. the versioning would be updated and you could no longer flash anything under "v2".. etc etc.

I'd love to hear from other G4 users if they have this menu value on their phones... would make it easier on me to know which updates are at which version.

It is not "settings > about", I used a secret code and scroll down
Code:
*#*#244773825625#*#*
Found in ATT G4 Forum XD
http://forum.xda-developers.com/att-g4/general/info-amazing-secret-cough-codes-t3201817
 
Last edited:

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  • 29
    This was not written anywhere specifically on the LG G4 forums that I could find. But every flash-addict needs to be warned. It is something you want to know before you continue tinkering.

    Several users (myself included) have made the unfortunate mistake of attempting to downgrade their bootstack (for various reasons) to a former version.

    DO NOT DO THIS (at least for the USA T-Mobile H811 version, and possibly other USA versions, per @autoprime)! It will result in a hard brick! Specifically, this results in the "Qualcomm QDLoader HS-USB port ( 9008 )" error. Connecting your phone to a PC will pop up with this active connection, but nothing else. There is no download mode. There is no publicly available fix as of yet.

    This WILL happen both through KDZ restore as well as flashing bootstack .zips.

    Yes, an official KDZ image can BRICK your USA phone, if you try to rollback.

    This is in stark contrast to other manufacturers (i.e. Samsung), where the attempt to flash an older bootloader/modem/radio will simply fail, but your phone is not bricked.

    I have conferred with @autoprime, who confirmed that with each OTA firmware release (on T-Mobile it was 10H, and now 10N), the version # increments. Flashing a lower version # will result in brick.

    I have searched far and wide for a DIY fix. Without the proper firmwares in the right format, as well as the right flashing software, your phone is done and must be sent in for LG repair.

    To check what antiroll-back version you are on, input this sequence in the dialer (T-Mobile and ATT) and scroll down:
    *#*#244773825625#*#*

    Flashing a bootstack version less than this # (through KDZ or zip) will brick the phone. You are free to flash anything equal or higher than the version listed.

    EDIT:
    The 20i MM update for the H811 is v2 antirollback. The 10n bootstack is also v2. So flashing between the 2 (returning from MM to Lollipop) should not hard brick the phone.

    EDIT 2:
    The 20o MM update is v3 antirollback. Once you go 20o, you cannot go back.

    For your flashing needs, I suggest you use LGUP and NOT LGFLASH, as LGFLASH will ignore the rollback flag and brick your phone without remorse!
    10
    thanks for the thread @waylo

    I have checked the most recent international builds and all are still on "v0". Tho that could always change in the future... but as of today... "v0"

    The original out of box Tmo h811 version was "v0"... after the first forced OTA it became "v1"... as of 10N it is now "v2".
    I do not have access to the latest AT&T, Sprint, US Cellular or Verizon bootstacks (seems there are no new KDZ's for them and no one has dumped the files) so I cannot confirm if AT&T, Sprint, US Cellular or Verizon's latest OTAs also move it up to "v2" or if still on "v1".

    Actually.. I'm not even sure if Sprint, US Cellular or Verizon got a 2nd OTA yet.. but I know AT&T has "10i". If any 10i users who are rooted could dump the bootstack for me and send it over I can confirm.

    Latest I know of for Sprint is ZV5.. thats "v1". US Cellular.. not sure.. but 10C was "v1". Verizon... again.. not sure what latest is.. but 11A is "v1".

    *edit*
    just checked US991 10D... still "v1".
    3
    and so is the new TMOBILE 20o.. is antirollback v3.?? so this means i cant go back to LP 10N i have not used 20o am still on LP 10N but i wanted to try MM so i havent decide wich to download.. i was aiming for the 20i.. but with the new released version not sure wich one to download
    Yep its antirollback! Once on 20o your on it for life! Its v3. Good thing LGUP has this warning.

    d7e7768e2451f7efacb2119d7dbcf7c8.jpg


    Sent from my LG-H811 using Tapatalk
    2
    That's a nice thought, but it will not be borne out until the next OTA comes out and we check the version. I wouldn't recommend you act on this supposition unless you have the time for a repair and a backup phone.

    It was just a shot in the dark...but i always read and am very careful what i flash...but on the other hand my best friend has a good bit of experience with Android repair and a very pricey computer and a rather nice jtag device...I'm just hoping lg isn't turning the way of Samsung and trying to block out development as it will be the reason if i ever leave lg devices...locking out development is a boner killer and i wont think twice but to move to more open oems...lol
    2
    ooh fancy! im not sure if g4 has that displayed in the settings > about screen.. but maybe? it's not on mine tho (H815 10C)

    But yes.. that would be what's being referred to in this thread. As your screen shows "1"... so any bootloader's at "v0" would brick phone... while any "v1" or higher" would work. and if you were to flash a "v2" bootloader.. the versioning would be updated and you could no longer flash anything under "v2".. etc etc.

    I'd love to hear from other G4 users if they have this menu value on their phones... would make it easier on me to know which updates are at which version.

    It is not "settings > about", I used a secret code and scroll down
    Code:
    *#*#244773825625#*#*
    Found in ATT G4 Forum XD
    http://forum.xda-developers.com/att-g4/general/info-amazing-secret-cough-codes-t3201817