Hi,
I have recently purchased a AR750s and I an unable to perform the debrick process EVEN on a windows machine, AND with a supposedly compatible uBoot from (Aug 16 2018 - 07:51:15). I have also updated to the latest stock firmware, but still unable to access the uboot interface.
I have tried also using a Linux machine, with the same results. There is no response from 192.168.1.1 at all no matter what i do.
I managed to resolve this issue. For reference, I had change to use a CAT5e cable. The cable that I was using was probably a CAT5 cable. Very obscure issue but there you have it.