There have been scattered reports of getting
ERROR_DRV_FAULT on ODrive v3.4. The circumstances that trigger this fault have been fairly elusive; we found it differs between boards, motors and bus voltage, in a fairly inconsistent way. Though we found that it seems to be sensitive to high gain settings. It seems about 5% of users are affected.
We hope to address all of the grounding related glitchyness in ODrive v3.5 where we plan to move to a 4-layer design with a solid ground plane for the logic side.
Meanwhile we found a fix that you can apply to your v3.4 board if you are having issues with DRV_FAULTs. You can change the ground that DVDD is bypassed to from AGND to the GND right under the DRV chip. This has fixed or significantly improved the situation for 4/5 people with the issue.
See the following instructions:
De-solder C35, then solder it on again in the configuration shown. Solder a wire as shown to the thermal pads of the M0 DRV chip. Note that you will need a fair ammount of heat/time to properly wet these vias.
Similarly flip C50 and solder a wire to the vias for M1 side, as per the above picture.