Question on backing up Magican ROM

[Jim diGriz]

I am trying to backup my Vodafone VPA (Magican) ROM as described in this Thread (http://forum.xda-developers.com/viewtopic.php?t=19500), but i seem to have a problem: I repeated the procedure five times. First the resulting files seemed to be identically but after opening them in a hex-editor the files are different from Position 0x034 to 0x17F. Is this normal? The file size is always 66847136 Bytes and the files match exactly except the 331 Bytes which are always different. Is there a solution? Or is it my fault? :?:

[Jim diGriz]

Seems like noone else got this problem?????
I´ve used 3 different computers now, but problem still occurs.
Please help...

[iDG]

The first 416 (0x1a0) bytes of a rom backup are some kind of header:

0000: 4d 41 47 49 43 49 41 4e 20 20 20 20 20 20 20 20 |MAGICIAN |
0010: 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 30 |0000000000000000|
0020: 31 2e 30 30 20 20 20 20 20 20 20 20 20 20 20 20 |1.00 |
... somewhat random stuff ...

(radio rom)
0180: 48 54 43 53 36 30 30 30 30 30 30 30 30 30 33 30 |HTCS600000000030|
0190: 30 30 30 30 31 36 31 38 44 32 44 30 c2 ee 13 de |00001618D2D0....|

(os rom, including Ext_ROM)
0180: 48 54 43 53 41 30 30 34 30 30 30 30 30 33 46 43 |HTCSA004000003FC|
0190: 30 30 30 30 45 36 32 33 34 39 34 46 fe 03 00 ea |0000E623494F....|


At offset 0x180 you can see
'HTCS'
<start address, hex 8, bytes>
<length, hex, 8 bytes>
<checksum, hex, 8 bytes> (the ascii rapresentation of the dword at offset 0x0030)

The random stuff is probably something left inside the ram of the device before the dump, but i've never tried to change it... Ok, I tried: the bootloader will report "not allow update". The "random stuff" is probably not really random. I will disassemble the bootloader, sooner or later.

The dword at offset 0x019C is quite likely the first dword of the rom, as the last dword of the dump is 'HTCE'.

As far as I can tell, yes the contents between 0x0034 and 0x017f are supposed to change every time you dump any part of the rom.