41CL MMU Backup

[twoweims]

(05-29-2020 04:07 PM)Monte Dalrymple Wrote:  Was the Flash at 0x3f1 empty before you wrote to it? What was the configuration you had previously stored at 0x3f1? There are locations in Page 804 that are used for internal stuff by YFNX and YUPS, and you are actually executing code transiently stored in this area when doing Flash operations. But that shouldn't matter when doing YMCPY. I'll try to duplicate what you are doing in the next couple of days and let you know.

Hello Monte, Thank you for responding.
I am not sure that I am even following a proper procedure for backing up.
My understanding is that to back up the entire state of the calculator so that I can recover from an extended period of battery removal that I should save copies of both page 800 and 804 to flash. We can assume I have nothing in pages 801, 802, and 803 for now. Is that a correct assumption?

is

Code:

    [ALPHA] 800>3F0 [ALPHA]
    [XEQ]  [ALPHA]  YFWR  [ALPHA]            

    [ALPHA] 804>3F1 [ALPHA]
    [XEQ]  [ALPHA]  YFWR  [ALPHA]

the proper way to perform this backup?

I did verify that Pages 3F0 and 3F1 showed YCRC value of 53D36BD2 before starting.
Afterward the YCRC values had changed, which indicated to me that I had written something to those locations.

I then removed the batteries for about 1/2 hour and have tried to figure out a procedure to restore from these backups. Is YMCPY the proper way to do it?

I am surely missing a key step in the process and appreciate your assistance.