Just to update, turns out my issue was the same as Moff's problem - choking on the LoadModule scsi.device part of startup-sequence. Finally got a keyboard, so was able to flash to the newer version of the ACA1221ec software. This fixed my issue.
Good to here that it worked for you to! I decided to install the latest version of AmigaOS, 3.1.4 using these two tutorials:
https://brotkasten.blog/2018/11/03/hyper-hyper-hyperion/
https://www.youtube.com/watch?time_continue=3328&v=H6PZm80rgTE
Everything worked fine except that the machine didn't boot up without holding the left mouse key during startup. I got the error message "MapRom already active, exiting!". Even when I had installed the latest ACA1221ec software the problem existed. To solve it I had to comment out the following row in my startup-sequence: C:LoadModule ROMUPDATE.
Just in case you, or anyone else, decides to install AmigaOS 3.1.4 with ACA1221ec and get the same error message.