Elegoo Mars 2 Pro - M commands mostly return just "ok N:X"

[TheCase]

I'm on Firmware V4.4.3-c2_LCDC/1620X2560 /F9.23 and the return values on the serial port are not returning what one would expect according the docs here: https://docs.google.com/document/d/14UBMO0Vhh9Lr0V3xcdetQ2_4UDnjFnho7OnbNxLOs3o/view#heading=h.yj17hhycvel4

For instance, while both idle or printing, the M4000 command simply returns "ok N:X" where "X" is an incrementing sequence . M4006 returns exactly the same output - zero information about the printer. It seems the only M informational commands that work as expected are M114 and M115. M115 returns "ok CBD make it.Date:Jul 3 2021 Time:10:42:39"

As such, the only things I can do with Mariner3D are upload, view and delete files. I cannot start prints, nor can I get any printer information while either idle or printing - everything results in "Unexpected Printer Response"

I know this is potentially more of a problem with my printer than it is a Mariner problem. I tried working with Elegoo support, but it seems they are mostly clueless about the serial port functionality. Figured I might have better luck understanding whats wrong by posting here. Thanks

[rudetrooper]

Did you update the printer recently? Chitu or Elegoo might have locked down the serial debug port.

[TheCase]

I did - I updated to 4.4.3 last week. I've only had my printer a couple weeks and only tried Mariner3D post-update - so I don't know if it ever would have worked with my printer.

[luizribeiro]

Can you try downgrading? Not sure which firmare version folks who use the Mars Pro 2 generally use. If anyone who has one could chime in it would help.

FWIW my older Mars Pro is the running 4.3.4...

[TheCase]

I suppose so, but I've heard enough horror stories about firmware upgrades on the Elegoo's that I'm hesitant to attempt a downgrade. I'll be curious of other's experiences.

Honestly while my current situation is a bummer, as long as I can remotely upload files (via SSH), I'm happy. Remote start and printer status would be nice but I'm not going to risk a braindead mobo for those features right now. Also, it sounds like the current 4.4.3 firmware is required to properly support CTB files created by Chitubox 1.9.0

[TheCase]

Heard from Elegoo support:

The motherboard of our machine is closed source, so these commands are currently not supported