And I've just read thisQuote:
So many people have said that booting from USB is impossible, including myself :). In fact it IS possible. USB device needs to have a MAC bootblock and a HFS partition. There were some guides on Morphzone. It works here, boot.img is loaded but MorphOS cannot continue booting for some reason. I guess that I should try some other USB drives :).
This sounds a bit different than just having a FAT formatted USB stick? Is this accurate?
Read it here: https://morph.zone/modules/newbb_plus/viewtopic.php?topic_id=7031&forum=11&start=2