For Sale: HP-71B MultiMod ROM Emulator

[rprosperi]

Which image file are you trying to send? Have you examined it (e.g. with text editor) to ensure that it is indeed ASCII HEX data?

You should NOT send it as binary, send as ASCII (default) as this is what it's expecting (ASCII HEX string data).

I'd connect it all up, adjust settings (disable binary and set AUTO) pull the jumper to reinitialize the MM and then tap enter to confirm it's responding.