The Museum of HP Calculators

HP Forum Archive 09

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ROM Swapping
Message #1 Posted by Speck on 16 Sept 2002, 12:58 a.m.

I read on that there is a ROM from I think an 39G that can be loaded onto a 49G. I just saw on the website that the HP's share the same processor (I've known about the Saturn for a little while) and some OS components. My question(s): did somebody have to tweak the 39G ROM to get it to go onto the 49G, or does it work automatically? And if it just works, has anybody ever tried going the other direction (49G ROM to 39G/40G)? I know nothing about the extra internals or the memory space available on any of them except for my 49G. I do not have access to a 39G or a 40G, nor will I try this anytime soon. It's just curiosity on my part, wondering if HP made their lives easier by making only one calc (hardware platform) and letting just the loaded software differentiate between the "flavors."

Re: ROM Swapping
Message #2 Posted by Ellis Easley on 16 Sept 2002, 1:38 a.m.,
in response to message #1 by Speck

I also read about that, and downloaded the files, from the website of one of the HP38G-39G-40G-49G developers, Jean-Yves Avenard ( ). I haven't tried it yet. I have noticed that both the 39G and 49G, when reset, display a copyright message for the MetaKernel, which started as an HP48G enhancement developed by Jean-Yves and others before they went to work for HP. There is some information about it on another of his pages ( ). You can see Jean-Yves' picture on a 49G by pressing [ON] and [F4] together and then pressing [VAR(J)]. After that, pressing [ON] will reset the calculator.

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