#1 HP Pavillion 17g121wm AMI Aptio V modding trials by MrPopz 12.04.2019 09:07

Hey everyone!

So I have an HP Pavillion 17g121wm with AMI aptio V, it's pretty modern and has the idiotic HP sure start on it with the 3 sources for bios authentication. :(

Nevertheless I tried modding the bios (I am bent on flipping the finger to hp, I hate the gpu settings on there) using a CH341a programmer and a clip using flashrom from Linux mint 19.2.

Few things to note with the programmer:

1. Had issues with flashrom recognizing the programmer from a live USB I had made on my custom desktop, not sure if it's just old or somethings else, Linux mint did recognize it plugged in though.

2. The programmer worked flawlessly on Linux as a hard install on a partition I made on a hp pro book 6450b next to win xp.

3. The programmer and clip were from Amazon (prime only, literally only one option, the clip had a couple)

4. Everything worked fine and the clip was a bit sensitive but programmer accurately recognized the bios clipping in the right pin order without any indication on the hp mobo.

5. DO NOT RESET CMOS AFTER FLASHING. I almost bricked it doing that, I'll explain below what happened.


Here's how it went down:

- Using flashrom on Linux (Sudo flashrom -p ch341a_spi r backup.bin) I backed up the bios just in case ( thank god I did that). I got an error only when I didn't clip it the right way, flashrom would warn that the chip wasn't recognized.

- I extracted the file as is using UEFitool to bin.

- I then took the extracted bios and opened it on AMIBCP to switch all access to USER from Default and saved it. (Took a while. I also disabled secured boot in all locations on the bios, one option was hidden in security that wasn't visible).

- I then flashed the bios using flashrom on the Linux using (sudo flashrom -p ch341a_spi -w bios.bin)

- it successfully erased previous bios and put the modded on there.

- Now came the problem, sure enough sure start kicked in and reflashed the bios from the backup source.

- I tried seeing what happens if I reset the cmos after flashing. BAD IDEA, I was sure I bricked it and needed a new module. Sure start tried to reflash itself but could not verify its own flash!! What's more, I had trouble erasing the chip and try again. I did eventually after restarting terminal and unplugging the programmer and plugging it back in. Only from now on, it could not verify the image every time.

- So I flashed the backup back in and laptop booted up just fine. I stopped trying after this,

- I would love to figure out how to disable this crap, I know it's on the mobo and I suspect some chips that could be one of the backups, but I'm afraid to even flash that source because the brain of the sure start module will prevent any kind of booting at that point unless it is somehow patched or spoofed.

If anyone has had any luck in figuring out anything on sure start and how to disable it or spoof it would be great. I am also willing to contribute anything I can to figure this one out, I am not giving into HP, but also not buying their crap ever again!!!

(PS. Is it possible to mod vBIOS on the amd chip to increase TDP and throttling temp?)

#2 RE: HP Pavillion 17g121wm AMI Aptio V modding trials by Lost_N_BIOS 12.04.2019 09:19

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Sure Start cannot be beaten, until someone figures out which chip the Sure Start Backup is located in, then we can try removing but I assume that will just case bootup failure full stop.
We tried to beat this good on a system with dual BIOS chips (Many have this, partial FD and ME on one chip, main BIOS contents in full or partial on the other), and sure start was not in either of those (replaced both at once, one at a time etc)
My advice, after MANY trial and errors is to walk away. Some parts of the BIOS can be modified (I can't remember what all we found, but we tested a lot - ME and ucodes I believe, some other areas too), but nothing we generally want modified in an actual BIOS mod, otherwise sure start recovery is invoked

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