That explains the crash very well!
OS/2 is extremely sensitive to mainboard changes, especially regarding the hard disk controller, BIOS settings, and hardware compatibility.
What is the problem?
A new mainboard means a different chipset, different controllers, and different hardware resources.
The existing drivers (especially for hard disks/SATA, possibly also ACPI or USB) often no longer match.
OS/2 only "notices" this at startup and crashes with a TRAP 000e as soon as an incompatible driver is loaded or an unknown hardware access occurs.
What can you do?
1. Adjust BIOS settings
Set the hard disk mode to “IDE” or “compatibility mode” (do not use AHCI/SATA unless you have a suitable OS/2 driver installed).
Set the CD/DVD drive to the same mode, if possible.
2. Boot with minimal hardware
Remove all unnecessary PCIe/PCI cards.
Connect only one hard disk and one CD/DVD drive.
3. Update drivers
If possible, boot from an OS/2 boot diskette or installation CD (e.g., eComStation, ArcaOS) and install the appropriate drivers for: SATA/AHCI controllers (e.g., DANIS506.ADD, AHCI.ADD/Look for the driver on the installation medium)
USB (if needed)
ACPI
4. Edit CONFIG.SYS
Check the CONFIG.SYS file for lines like BASEDEV=...
Remove or comment out drivers that are no longer needed (such as old controller drivers).
good look ....