HP-41CY re-initialization ROM

[PeterP]

(10-27-2019 03:00 PM)Jurgen Keller Wrote:  While doing further test runs I think I should also delete the polling vectors FF8, FF9 and FFA (or even more?) in all RAM pages of the active bank. I guess I should install a handler for FF9. I'll give it a try.

Wonderful stuff Juergen! It was the last piece of code I was thinking of writing one day as I felt it is missing in the Open Source, and you have done it now! This means CYs and Ramboxes from both W&W and Eramco can now be recovered.

I love the location of the InitRom in page 4!

One thing I wonder (and that has kept me from writing it out) is how to avoid garbage in the polling points of the pages E & F (in your case) where you have the OS. I always thought that if I put the InitRom in page 4 (I was thinking page 6, but it doesnt really matter I think) and the OS into pages E&F that I would not easily be able to clear the polling points there in case they got corrupted. So my thought was that I have to have the OS in the InitRom also and copy it from there to page 8 & 9, using that the difference between OS/A and OS/B is very small (just a couple of bytes) so one would copy OS/A twice and then overwrite the correct spots to make it OS/B.

Would love to hear your thoughts, I'm probably missing a whole bunch here as you clearly state it works already neatly and is recovering CYs (of which you - similarly amazingly - have it seems a never ending supply!

Great work and I love to see this happening!

Cheers

PeterP