ROM dump for emu42


I have a 42s and a 48GX and I've read the article on this site about dumping the 42s ROM to the 48. I've been able to do this but my question is what to do with it after I get it transfered to the PC. I recently found emu42 and since I have the ROM image available I'd like to use it to run emu42 but I need to know how to convert these text strings from the 48 to something that emu42 can use. What's the best way to concatenate the pieces and what else has to be done? It appears that what the 48 receives is just a copy of the LCD from the 42s since every line is preceded by the XXXX: address location. Are these addresses part of the actual ROM? Do I need to remove them to use with emu42? I'm sorry if this subject has been covered before, I'm rather new to this forum (I've only been lurking for about a month or two, but I've been using HPs for years =). Thank you in advance.

Virgil Taylor



1) Once you have all the pieces, put them together into one large file that should look something like




... and so on, all the way up to ...




(The file size should be 192KB)

2) Then run "DMP2ROM" from the command prompt on your file. A binary ROM file (size 64KB) should then be produced.

3) Also from the command prompt, run LEWISCRC on your new binary ROM file. LEWISCRC will compute the checksum of the ROM and tell you whether the dump is valid or not. If it is not then there is most likely some small error that has happened during the ROM dump. Check your dump file and try again. If LEWISCRC says "CRC ok!" then you're ready to go for the last step.

4) Put your ROM binary alongside a suitable KML. (Remember to make sure that the name of the ROM binary is identical to the name referred to in the KML). Then just run Emu42 - voilà!

Welcome to the club!

Erik Ehrling (Sweden)


Edited: 5 Apr 2004, 12:33 a.m.


A new ROM upload method was announced here:

The program Erik spoke about are at and



Erik and Christoph,

Thank you for your help and info (and the outstanding software =)

Virgil Taylor

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