Updating the HP-41CX OS code (really 41CL)

[hth]

I am working on the HP-41 OS (mainframe) code to give more extended memory by extending it into page 4 and beyond (to be configurable), for a start.

There are a couple of questions that I need to ask in order to hopefully reduce problems later.

I currently assume that I can make use of previously unused areas in the module, is this a problem? Has some areas already been claimed? (I especially need the area at 0x3c00 to extend the backstep routine at 0x3b14 and the extended memory initialization code.)

As this is mainly intended for the 41CL, there is a problem with the .mod file format as it cannot handle 16-bit images. Has then been addressed in some variant of that format already? I would like to have a "MOD2" format or something that do not pack bits and allow for the turbo bits of the 41CL.

There was a desire to make this code base open source in the past, did it actually happen? It would be nice to be able to do it more in the "open"...