I'm working on restoring old Compaq Deskpro EN 6266 to a factory setup.

I found restore disk + Win98se that are compatible with each other (Also, it's the lastest version of restore cd i could find):
Restore CD v5: https://archive.org/details/restore-cd_202106
Windows 98se: https://archive.org/details/compaq-cd-for-mic … perating-system

All is good during first few steps. I can repartition/format the disk, copy all the files both from restore cd (including selection of software) and from Windows CD. And then it configures some stuff. By that time, it has once booted from HDD now. But once i restart after configuration step, it goes to boot loop. It barely shows the windows boot logo (with Compaq branding) and immediately resets. And it does it indefinitely.

Does anyone have any suggestions i could try?

Things i've tried with no change in behavior:
Multiple different known good RAM sticks.
2GB HDD with FAT16 and 32GB SSD with FAT32.
Different video cards.
266MHz Pentium 2 and 550MHz Pentium 3 CPUs.
Multiple CD-ROM drives.
Burned the CDs multiple times.
I can also confirm that the machine is rock-solid with my own custom install of Win98se.

I would love to get complete out-of-the-box experience for this Compaq. It's a beautiful machine.