iPad iOS Firmware iPad ipsw firmware download that provided by Apple, when you do the relevant operation at your own risk.

iPad Pro 4 (12.9-inch)

iPad Pro 4 (12.9-inch) Type and Models :
  • A2229
    • iPad8,11
  • A2069, A2232,A2233
    • iPad8,12

The signed firmware that you can restore the file by MFC Software or by iTunes.