I checked the code - yes it's according to the wiki code. Odd that this hasn't happened before...
I will need to check what delay is needed to work on the 2MHz machines.
I imagine as little as a change to 2 instead of 1 might solve it but I'd have to test to be sure.
lis 1 ; Small delay
.multiblitSavePixelDelay:
ai $ff
bnz .multiblitSavePixelDelay ; loop if not 0 (small delay)
I got development firmware from Evie for the BackBit to solve some issues, let me know if you need it.
You can twist to jump 5 pages, menu covers more of the screen and the XDC opcode is fixed so everything using the Sleisza sound routine won't crash anymore.
EDIT:
Tried changing "lis 1" to "lis 2" in the multiblit-routine - solved the problem. I have updated the wiki-page.