Questions on DFU mode

[tru3lies]

Apple noob here with some questions.
At which level does the DFU mode work on the device which should be recovered? I guess it is some lower level and not userland, but I don't know for sure.
Firmware, kernel, single user or maybe even SOC level?
Many (ARM) chips have a very low level mode which runs directly from the chip and is often used to get the actual firmware on the device, see for example: https://linux-sunxi.org/FEL/USBBoot
Is it possible to make an (encrypted) backup from DFU or maybe some other boot modes and decrypt it, provided you know the correct passphrase ?

 

[Gnattu]

DFU is in the SecureROM embedded in the M1 SOC, which means you can always use DFU to flash your device unless the SOC itself is dead. It is almost impossible to brick an Apple Silicon Mac, using only software, in a way that cannot be recovered externally by an end user who has another device to perform the DFU mode rescue.

Similar functionality is also presented in the T2-equipped Macs because T2 runs a subsystem itself.

I have not personally tried backup from DFU yet, but that option does present in the Apple Configurator 2.