MDM6610

The Qualcomm MDM6610 is the baseband chip used in the iPhone 4S.

Baseband Firmware
The firmware for the baseband chip comes in Trek-X.X.XX.Release.bbfw files (with X being the version). The BBFW file is just a renamed standard ZIP archive and contains a couple of .mbn files which are all digitally signed with a certificate from Qualcomm. Qualcomm's Senior Engineer Shital Mehta is involved with the programming of the firmware. The amss.mbn file is an ELF file:

Mac OS X file command output
file Trek-1.0.11.Release/amss.mbn /Trek-1.0.11.Release/amss.mbn: ELF 32-bit LSB executable, ARM, version 1, statically linked, corrupted section header size

iPhone 4S
1.0.11   5.0     (Build 9A334) 1.0.12   5.0.1b  (Build 9A402) 1.0.13   5.0.1b2 (Build 9A404) 5.0.1  (Build 9A405) 1.0.14   5.0.1   (Build 9A406) 1.2.01-1 5.1b    (Build 9B5117b) 1.4.00   5.1b2   (Build 9B5127c) 1.5.04   5.1b3   (Build 9B5141a) 2.0.10   5.1     (Build 9B179) 2.0.12   5.1.1   (Build 9B206) 2.8.01   6.0b    (Build 10A5316k) 2.8.04   6.0b2   (Build 10A5336d) 2.8.07   6.0b3   (Build 10A5355d) 3.0.00   6.0b4   (Build 10A5376e) 3.0.04   6.0GM   (Build 10A403) 6.0    (Build 10A403) 6.0.1  (Build 10A523) 6.1b   (Build 10B5095f) 6.1b2  (Build 10B5105c) 6.1b3  (Build 10B5117b) 6.1b4  (Build 10B5126b) 6.1b5  (Build 10B142) 3.4.01   6.1     (Build 10B142) 6.1.1b (Build 10B311) 3.4.02   6.1.1   (Build 10B145) 6.1.2  (Build 10B146) 3.4.03   6.1.3b2 (Build 10B318) 6.1.3  (Build 10B329) 4.3.01   7.0b    (Build 11A4372q) 7.0b2  (Build 11A4400f) 4.4.00   7.0b3   (Build 11A4414e) 4.4.03   7.0b4   (Build 11A4435d) 7.0b5  (Build 11A4449a) 7.0b6  (Build 11A4449d) 5.0.00   7.0GM   (Build 11A465) 7.0    (Build 11A465) 7.0.2  (Build 11A501) 5.0.02   7.0.3   (Build 11B511) 7.0.4  (Build 11B554a) 7.0.6  (Build 11B651) 5.1.00   7.1b    (Build 11D5099e) 7.1b2  (Build 11D5115d) 7.1b3  (Build 11D5127c) 7.1b4  (Build 11D5134c) 7.1b5  (Build 11D5145e) 5.2.00   7.1     (Build 11D167) 7.1.1  (Build 11D201) 7.1.2  (Build 11D257) 5.2.01   8.0b    (Build 12A4265u) 5.3.01   8.0b2   (Build 12A4297e) 5.3.02   8.0b3   (Build 12A4318c) 8.0b4  (Build 12A4331d) 8.0b5  (Build 12A4345d) 5.4.00   8.0GM   (Build 12A365) 8.0    (Build 12A365) 8.0.1  (Build 12A402) 8.0.2  (Build 12A405) 5.3.02   8.1b    (Build 12B401) 5.4.00   8.1b2   (Build 12B407) 8.1    (Build 12B411) 8.1.1b (Build 12B432) 8.1.1  (Build 12B435) 8.1.2  (Build 12B440) 8.1.3  (Build 12B466) 8.2b   (Build 12D436) 8.2b2  (Build 12D445d) 8.2b3  (Build 12D5452a) 8.2b4  (Build 12D5461b) 8.2b5  (Build 12D5480a) 8.2    (Build 12D508) 5.3.02   8.3b    (Build 12F5027d) 8.3b2  (Build 12F5037c) 8.3b3  (Build 12F5047f) 5.4.00   8.3b4   (Build 12F61) 8.3    (Build 12F70) 5.3.02   8.4b2   (Build 12H4086d) 8.4b3  (Build 12H4098c) 5.3.03   8.4b4   (Build 12H4125a) 5.5.00   8.4     (Build 12H143) 8.4.1b (Build 12H304) 8.4.1b2 (Build 12H308) 8.4.1  (Build 12H321) 5.3.02   9.0b    (Build 13A4254v) 5.3.03   9.0b2   (Build 13A4280e) 9.0b3  (Build 13A4293g) 5.3.04   9.0b4   (Build 13A4305g) 9.0b5  (Build 13A4325c) 9.0GM  (Build 13A340) 9.0    (Build 13A344) 6.0.00   9.0.1   (Build 13A404) 9.0.2  (Build 13A452) 5.3.04   9.1b    (Build 13B5110e) 9.1b2  (Build 13B5119e) 6.0.00   9.1b3   (Build 13B5130b)

External Resources

 * Reverse-engineering a Qualcomm baseband - Video
 * Reverse-engineering a Qualcomm baseband - Slides