Well for that i can’t vouch it… but as you said, this is a fun project.
Seems it uses the IPISB-NK (Lavaca3-SB)
This is 3rd Core Gen machine and this kind of bios is usually among the easiest to mod.
Follow this guide and do please make SPI backups with the Intel FPT tool from the ME8 package.
For flashing this tool can work also, if the motherboard has an ME_Jumper/Manufacturer (Bios_Config/Rom_Recovery).
Besides normal HP tool for flashing, if it fails due to security issues (Its a mod file…), it remains an SPI programmer like a cheap CH341A.
As new user level, you can attach files for now, but you can share a linked file on a sharing service of your choice.
Good luck, all the best.