SDX55M

The Qualcomm Snapdragon X55 5G Modem is the baseband chipset used in the iPhone 12 mini, iPhone 12, iPhone 12 Pro and iPhone 12 Pro Max.

This is the first baseband chipset in an Apple Mobile Device to support 5G communications, capable of providing download speeds as high as 7.5 Gbit/s.

it is also known as  in firmware.

Known Firmware Versions
1.00.03-5  14.1           (Build 18A8395) 1.14.04    14.2 beta 4    (Build 18B5083a) 1.14.05    14.2 RC        (Build 18B91) 14.2          (Build 18B92) 1.31.02    14.3 beta      (Build 18C5044f)