GSM-Forum - View Single Post

ldril · 01-15-2002, 08:47

The bytes can be modified and the checksums can still be the same. For example if you calculate the checksum by adding the bytes and discarding the carry then if you have 13 54 21 it will give the same checksum as 15 53 20. So in theory you can modify the MCU or PPM and then fix a word somwhere where is not needed and adjust the checksums to be the same.

So if the checksums are adjusted in this way will the phone work without logging?

What exactly is the MSID? Is it calculated from smth? Where from?

Mircea

P.S. Sorry for the double posting.

01-15-2002, 08:47	#4 (permalink)
ldril Insane Poster Join Date: Jan 2002 Location: Romania Posts: 61 Member: 8505 Status: Offline Thanks Meter: 0	The bytes can be modified and the checksums can still be the same. For example if you calculate the checksum by adding the bytes and discarding the carry then if you have 13 54 21 it will give the same checksum as 15 53 20. So in theory you can modify the MCU or PPM and then fix a word somwhere where is not needed and adjust the checksums to be the same. So if the checksums are adjusted in this way will the phone work without logging? What exactly is the MSID? Is it calculated from smth? Where from? Mircea P.S. Sorry for the double posting.