Hello friends. I'm here with a little question about one study drive (not a real case).
This ST3750535AS becomes RDY when turned on with MRT Pro, but becomes endless BSY when trying to identify with Seagate F3 factory tool.
Running in terminal mode I get the reset code properly on output:

Rst 0x20M
RW: Disc Ctlr Initialization Completed.
(P) SATA Reset

but when I try access with Ctrl+Z I don't have any answer. Nothing changes.
Drive doesn't sound anything weird on any turn on attempt.
If someone could teach me what to try next, at least to get terminal access, I would really appreciate.
Thank you so much for any reply.

I have same issue with ST31000528AS has head issue and no terminal log.
I have tried with a working one that same model. Same . No terminal value. I tried firmware unlock with mrt. Terminal logs seeing.
Maybe this models usual issue

But mine different than yours. I have see empty terminal
You have some logs

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I believe I will probably need to short circuit the 3.3V pin to get terminal access, but I really don't know which ones.
This is the PCB

Thank you... I'm so used to do this on Rosewood family, but didn't had any case with other families. Now I have terminal access using only the firmware unlock tool.
Thank you very much.
Now I will try to analyse it.

HddDonorMarket, Failed head here too. I believe it is the common behavior of this models.