Hello everyone, new to the forum, new to this topic. I've been beating my head against the wall trying to flash my modded Bios for PCIe NVMe boot on my HP Compaq Elite 8300 convertible Minitower PC. Been trying everything I can find about this. And not having much luck in general, or with most tools as far as reading, backing up, and flashing. MMtools worked for the mod, I've followed the directions using mmtools (from guide on win-raid) to add mod. Don't think that's the issue. It's the new security added by the last few Bios updates from HP. I installed to the latest vers: (K01 v03.08)(sp95971.exe) just prior to trying this mod. My feeling is the mod might have taken with an older BIOS vers... Anyway... Seems the bios is locked up tight now.

Might there be a way to change the (checksum, HP signature, whatever portion of the modded Bios to act as if it is a new update)? When I used the DOS vers of HP's flash tool, it actually allows it to load half way, then says "invalid BIOS file". Say name the modded file to v03.09 and find that portion of the "raw / original" bios file and update it as well while doing the NVMe mod? Some basic trick to fool the flash tool. Or just creating a new embedded checksum and add it to the mod?... Thinking out loud with minimal experience.

I could use some clarity on the Intel flash tool from the CSME drivers / tools, and if I got the correct one, and or, does it even work with my system, download from Intel... This is what I found on Intel's download site:
ME_SW_2141.15.0.2511.zip

I'd like to find a solution for myself and anyone that has this system, with a nice vid card it really does well, hoping to get the added speed from the NVMe drive.

Also added a small, pertinent HWINFO.txt file of my system

Bios comparisons:
Latest: (K01 v03.08, sp95971.exe)
When it changed: (K01 v02.98, sp71019.exe)
Before security change: (K01 v2.83, sp59693.exe) or (K01 2.90, sp63016.exe)

My System:
Windows 10 Pro (x64) Build 19044.1387 (21H2)
Version 10.0.19044 Build 19044
System Mftr Hewlett-Packard
System Model HP Compaq Elite 8300 CMT
Processor Intel(R) Core(TM) i7-3770 CPU @ 3.40GHz, 3401 Mhz, 4 Core(s), 8 Logical Processor(s), E1, Ivy Bridge-DT
BaseBoard Mftr Hewlett-Packard
BaseBoard Prod 3396, Intel Q77 (Panther Point DO)
BIOS Version Hewlett-Packard K01 v03.08, 4/10/2019
SMBIOS Version 2.7
Embed Cntr Ver 255.255
ME Version 8.1.72.3002
BIOS Mode UEFI
SSD PCIe x1 Silicon Power US70 PCIe Gen 4 x 4 M.2 2280, supports NVMe 1.3

Thanks in advance for any advice / help.

The correct tools (Intel FPT tool) for ur HW generation (IvyBridge) its ME8/8.1 package, got get it. Wot u refered is a simple driver of the ME for windows OS...not the tool package.
OEM machines like ur HP and other brands fail on flashing mod files due to security implemented.
Best option for now (Beside an SPI programmer) is the use of the Intel FPT tool to dump (Save an image for recovery possibilities), then edit/mod the dump to NVMe and try to flash it back again with same tool.
This tool requires the full access to bios regions, that sometimes r locked (Bios/FD/ME regions), if so it must be unlocked first for success in all this operations.
Quick test of access is trying to flash the same untouched dump just made, as the dump operation is just a reading it will not fail but when writing it needs the full access to bios region, same happens to update the Intel ME FW.

Intel (Converged Security) Management Engine: Drivers, Firmware and Tools