Error  libusbrestore: error 21 [com.apple.MobileDevice.MobileRestore – 0x15 (21)] 

I have 2 MacBooks pro M2 13'3" Touch Bar that began to have anomalous behaviors of the functions of the systems, ending up affecting our Iphones, Apple TV, Ipads. Imac, mac mini, and other Android or PC devices, related to our work. 

The problem in the M2 13'3" Touch restoration process did not end satisfactorily, starting from the DFU state, completely restoring firmware and system, reaching the final phase of loading, we got a message of loss of connection with the device, with the message with the following error: 

 libusbrestore: error 21 [com.apple.MobileDevice.MobileRestore – 0x15 (21)] 

Now immediately when you turn on the computer the support.apple.com/mac/restore message comes out and I have not been able to return to DFU mode, someone can help me, I leave you the account of our experience so far 

Thank you to everyone who can help us 

1.- With a normal restoration, the same behaviors continued to appear shortly, so after even having been in the official technical service on our small island without solving it,  

2.- Having knowledge in algorithm and mathematical development, we decided to restore the devices ourselves, we registered as developers, we documented ourselves for several weeks. And at the same time we also collaborated with other  system developers, where Apple partners such as Wmware and others confirmed to us, that there could be anomalous behaviors, when a code was introduced, in the preload system phase of the system, which would have the objective of etrigeres to the dmbus services and the user account administrator, introduce a ghost user with a level of simulating being in a managed MDM environment. 

3.- We proceeded to restore our iPad, iPhone from the "Apple Configurator" tool knowing that we were starting from a computer that could be contaminated, obtaining a double authorization reliability certificate from both APPLE and AZURE, it seems that our devices have returned to normal behavior, although we keep them under observation to see their evolution