09-11-2021, 01:24 PM
Doing the installation on a UEFI system leaves the SSD (and the HDD you tried) configured to only be bootable on a UEFI system.
You can check whether the Athlon system's BIOS has any UEFI support and try enabling it if so, but I suspect it is too old for that. Can the Athlon system boot from any form of USB device other than a HDD/SSD (e.g. USB CD-ROM or USB flash drive)? Failing that, does your Ryzen system support "Legacy" or "CSM" as an alternative to UEFI?
You can check whether the Athlon system's BIOS has any UEFI support and try enabling it if so, but I suspect it is too old for that. Can the Athlon system boot from any form of USB device other than a HDD/SSD (e.g. USB CD-ROM or USB flash drive)? Failing that, does your Ryzen system support "Legacy" or "CSM" as an alternative to UEFI?