Hi,
Since I got no response, I started looking into things myself, but my brother was a little quicker and already came up with this patch.
The SAT menu is replaced with a menu item for changing the phone code. Alternatively we're currently trying to protect the SAT menu with the phone code. Looks feasible. We don't know how to entirely remove the SAT menu, which would be another nice option
For now, this will have to do:
;REPLACE SIM APPLICATION TOOLKIT MENU
;
;Firmware: M55 FW91
;Author: LittleBro
;Release: 2005-01-29
;Description: substitutes SAT menu with menu item to change phone code
;
;
;entry points, SAT menu -> change phone code
;
0x3685CE: 529C 56B0
0x3685D2: 5A9C 56B0
;
;rename menu item
;
0x36861F: 273A27 06F305