@george1421 My original FOS image is the latest available at Kernel Update GUI page, which currently is 4.19.6 (both bzImage and bzImage32)
I just finished one of the 2 machines with systems as described in OP. The capture job succeeded with not much as a single warning! The system with American Megatrends BIOS is also smoothly past the point in which the issue was happening. I also noticed another change, all of these machines sometimes got stuck in iPXE boot while loading “/default.ipxe”, at 0%, and forced me to reboot lots of times until randomly it boot correctly. After changing kernel and init versions, that problem vanished (I don’t know if things are related, tho).
My last machine with legacy Phoenix Awards BIOS did not complete the capture job, but looking at partclone.log I found out a bad block issue. I’m now trying to capture it using DD method, which increased time but is worth the test. I’ll report on it later.