
MPU... but do you know from what camera? K429 rings a bell?
Anybody?
Well, that's EOS R Battery grip!


Interesting thing is that you won't get shell unless poked RST pin (not sure to what level, i just attached my UARTs TX temporary and pressed any key).
EDIT: this may be related to me having grip on/off switch in off position when the tests were done. YMMV.
You need to almost completely disassemble grip first. It will not work without camera attached.
More details on MPU itself in
DIGIC 8 MPU investigationIf you come here from Twitter, please note that post thumbnail had wrong pins described for RX/RST (they were accidently shifted to the right)
