MDM6600

This is the Qualcomm MDM6600 baseband chip used in CDMA devices.

iPad 2 (CDMA) and iPhone 4 (CDMA)
NOTE: The iPhone 4 (CDMA Model) supports all versions (except 4.3 and 4.3.*), while the iPad 2 (CDMA Model) exists since iOS version 4.3. Nobody tested if 4.2.x would run on an iPad 2 (CDMA), since you cannot downgrade without SHSH blobs and Apple has never signed them for it. 1.0.05 4.2.5   (Build 8E128) 4.2.6  (Build 8E200) 1.0.06 4.2.7   (Build 8E303) 4.2.8  (Build 8E401) 4.2.9  (Build 8E501) 4.2.10 (Build 8E600) 2.0.04 4.3     (Build 8F191) 4.3.1  (Build 8G4) 4.3.2  (Build 8H8) 4.3.3  (Build 8J2) 4.3.4  (Build 8K2) 4.3.5  (Build 8L1) 2.1.10 5.0b1   (Build 9A5220p) 2.1.15 5.0b2   (Build 9A5248d) 2.1.16 5.0b3   (Build 9A5259f) 2.1.19 5.0b4   (Build 9A5274d) 2.1.21 5.0b5   (Build 9A5288d) 2.1.23 5.0b6   (Build 9A5302b) 3.0.01 5.0b7   (Build 9A5313e) 3.0.03 5.0GM   (Build 9A334) 5.0.1b1 (Build 9A402) 5.0.1b2 (Build 9A404)