How do I Downgrade from OS 2.09 to 2.04?

[toml_12953 Profile]

I have an fx-9860G II SD Power Graphic 2 that came with OS 2.04. The first thing I did was to "upgrade" it to 2.09. It won't run Edit 1.60. I don't know if 2.04 can run that editor but I'd like to try it. The 2.04 upgrade won't let me install it because my current version is later. Is there a way to bypass the version check in the installer or otherwise get around the limitation?

Thanks,

Tom L

[Ford Nucleon Profile]

Did you find a way to downgrade?

[SimonLothar]

The Edit 1.6 problem has been solved here.
In case of this SH-3/SH-4A problem, a downgrade would not have been helpful.

[Ford Nucleon Profile]

I wanted to downgrade for a different reason as my calc won't run most of my games now. Is there a way?

[SimonLothar]

I wanted to downgrade for a different reason as my calc won't run most of my games now. Is there a way?

The reason for addin-incompatibility often is the MPU. You cannot fix that with OS downgrading.
Some time ago, I did downgrading with CASIO update-packages. Instead of following the official instructions and using the OS updater, I used the bootcode-updater. The bootcode-updater does not care for the version of the actually installed OS. Following this way I just downgraded my fx-9860GII (SH-4A) from 2.09 to 2.04. I did not encounter any problems.