[Success] Dell Latitude 5591 Preserves HAP Bit through BIOS Updates/Recovery/Resets

[Espionage724]

With BIOS updates and USB recoveries and CMOS resets, the HAP bit is seemingly preserved! I believe I did it back on 1.2# but it's still good on the latest 1.34 BIOS.

It interestingly passes Dell's trusted firmware checker too even though the platform hardware's firmware was technically modified outside the factory :p

I've been running with ME disabled on this laptop for a while now Linux, Windows 10/11, and recently FreeBSD 14.1 all without any noticeable issue.

[MonterLuis]

Hello, I have read about how to disable the ME, but I am still worried about making a mistake, as I had just seen the Intel's processor of your laptop is gen8, right? Either a i7 8850H, an i5 8400H or 8300H (coffe lake, both 3). Mine is an i7 8665U, whiskey lake. May I ask the exactly steps you follow to achive that on your laptop? Mine is a thinkpad x1 yoga gen4. I don't know the all the precautions I have to take to not destroy. I have so many questions, did you unsolder the bios flash chip? I plan to buy an exactly equal chip to load the bios and then exchange it to have the original as a backup. I appreciate any help.

[Espionage724]

I have a picture: https://www.facebook.com/share/p/PydSrvzDugHZ2D89/

I used a SOIC clip on the BIOS chip while it was on the motherboard. Kind-of tricky with it being WSON but the SOIC clip I used had curved pins that happened to meet the pins while still being able to clip onto the WSON chip!

I didn't de-solder the chip mainly because I don't have a soldering station or any clean way of trying to do that safely :p But that would likely be far easier than trying to get a SOIC clip onto WSON! I have a Pomona clip and I think I may have used small pliers to bend the clip's pins to either get more of a curve or possibly straighten them out to touch the WSON's pins better.

I have some notes here: https://wiki.realmofespionage.xyz/bios:notes:rpi_flashrom

I basically dumped the BIOS from the chip, used me_cleaner to set HAP bit (didn't delete partitions), and re-flashed the me_cleaner'd BIOS back to the BIOS chip with a hardware flasher (Raspberry Pi + SOIC clip on GPIO pins; flashrom on the RPi to read/write BIOS chip). Aside from needing a patch for newer ME platforms/Coffeelake, the chip dump/flash and me_cleaner process was mostly the same as a few other Skylake boards.

---

Iirc there's something about a voltage on some BIOS chips (3.3v?) and standby voltage, or something like the motherboard supplying voltage to the BIOS chip and that not being ideal while connecting a hardware programmer to the BIOS chip at the same time. I don't recall running into that being an issue and think I flashed the chip with the laptop battery and CMOS batteries still connected (no AC adapter plugged in).