If it is short, IMEI in Siemens C55 to change it is IMPOSSIBLE. Now I explain, as as. In Siemens C45, and earlier phones, IMEI it is stored only in area EEPROM, therefore it changes on absolutely anyone without any problems, at unlock.
In Siemens A50 and in more senior models IMEI it is stored already in two places, in EEPROM and in a special, unitary programmed microcircuit (PZ and * 1059. If with change IMEI, stored in EEPROM, problems both were not, and are not present to change contents of a microcircuit of a ROM only program methods it is impossible.
And the insertion of phone compares these two IMEI and if they do not coincide phone does not work. From the aforesaid it becomes clear, that if to alter A50 in C45 (there is such "technology", only, except for zalivki fullflesha, it is necessary still at least perepajat a pair rezistoro and * 1074 That change IMEI in such phone becomes possible because insertion C45 of concept has no about existence IMEI, taking place still somewhere, except for area EEPROM. So, only theoretically, decisions of " our problem " two, but I yet did not see concrete realization of any of them. For now we shall consider only theoretically possible variants:
1.