My board is currently on 2.1 (UPA1AM21).
5.0 BIOS says to make sure 4.0 is installed first.
4.0 says 1.8 is installed first.
1.8 says downgrades are not possible. How to proceed?
I ended up flashing 4.0 and then 5.0, so far no remarkable issues.
the instructions specify that you need at least BIOS R1.8 in order to upgrade to R4.0, so no need to downgrade as you noticed.
Thanks for the feedback, we will review the instructions to make them more clear.