Interesting, comparing against the 1050 USDoubler ROM, it starts out with exact same header, first Diff is at $1A,$1B, then $43,$44, $46, $49, $4C, $4E, then pretty much different past that.
Near the end of the ROM, $0FA8 is the text " DISK ERROR "
$0FB9 "START to restart"
$0FE5 "SPACE Change item"
EDIT: I see these 3 same strings in the working USDoubler 1-4 ROM as well. This appears to be a variant of US Doubler.. maybe corrupt or, the drive # 5-8 version?
EDIT 2: the 2 compare exactly the same from $0942 to the end
Guess I'll have to burn it to a 2732 and try it
Edited by Nezgar, Sun Feb 4, 2018 2:36 PM.