i've been tying to put an ME7.1 and an ME7.5 into boot mode but when i ground the pin suggested i get no response from the ECU when using nefmoto.
You need to use a bootmode tool like Galetto or Minimon to talk with the ECU in bootmode.
"Normal" OBD tools talk to the ECU using the KWP2000 protocol, this is only possible when
the ECU is running normally.
At least it seems you brought the ECU successfully into bootmode, since the NefMoto flasher
could no longer connect after you grounded the bootpin
.