No Cellular Services: Most A4 bypasses do not fix the underlying GSMS/Activation records on Apple’s servers. Consequently, the device can usually only be used as a "Touch" device—Wi-Fi works, but cellular calls and SMS usually do not.
You might ask: Why not use iRemove, F3arRa1n, or checkm8-based tools? A4 Devices iCloud Bypass - Silv3rCube
A4 devices usually require putting the phone into DFU mode manually. Compatibility and Limitations No Cellular Services: Most A4 bypasses do not
: Designed with a simplified interface to automate the complex process of exploiting the A4 chip's bootrom vulnerability. A4 Devices iCloud Bypass - Silv3rCube