Reboots during installation on system with AMD Athlon II X2 260 Processor

[comet]

Trying to install OPNsense on a system with the following specs:

AMD Athlon II X2 260 Processor
3.20 GHz
Cache RAM (L2): 2MB
Installed Memory 3072 MB /PC3-10600

This system has a BIOS.  We tried the VGA version and the serial version, both of which rebooted during install, and the DVD version would wouldn't boot at all (but we had it in a USB stick so probably no surprise there).

Just before it fails these are the last things it prints on the screen:

Code Select Expand


Trying to mount root from ufs:/dev/ufs/OPNsense_install [ro,noatime]...
da0 at umass-sim0 bus 0 scbus 4 target 0 lun 0
da0: <Multi Flash Reader 1.00> Removable Direct Access SCSI device
da0: Serial Number (a hexadecimal number)
da0: 40.0000MB/s transfers
da0: Attempt to query device size failed: NOT READY, Medium not present
da0: quirks=0x2 <NO_6_BYTE>
GEOM: da1: the secondary GPT header is not in the last LBA.
GEOM: diskid/DISK-(some hexadecimal digits): the secondary GPT header is not in the last LBA.

Right after printing that last line, the screen goes black for a short bit and then the BIOS boot screen appears.  The installation to the hard drive apparently never even gets started, because after it reboots it goes into Ubuntu which is what was previously on the drive.

We also tried the fix at https://forum.opnsense.org/index.php?topic=13564.msg62529#msg62529 but that accomplished nothing, after entering those lines at the OK prompt the system still rebooted at that same spot in the install.

Anything else we can try to make OPNsense install?

[comet]

Just to update this, today we tried starting out with an old version, 17.7.  It installed fine, so we did successive upgrades and got as far as 18.7 with no problem.  Then when it attempted to install 19.1, that is where it went into the reboot loop.

In a desperation attempt we also tried doing a MBR install and that made no difference, it still went into the boot loop as soon as we tried to upgrade to 19.1, and we even once again tried the fix at https://forum.opnsense.org/index.php?topic=13564.msg62529#msg62529 but it still doesn't help.

Is there really no fix for this?  What happened in 19.1 that made the upgrade go bad?