May be interesting...
I just updated 3790 and compare gmapprom.img with file from rutracker. They are not the same.
Compare 34xx.img & 37xx.IMG
0000000F: F2 D6
00000024: 50 5E
0000003C: 09 0B
0000003D: 16 00
0000003E: 2C 27
0000003F: 0D 34