Hi all. I’m new to this hobby and I have a problem that’s driving me insane. I bought a used P4 and all was good on the test flight, no issues at all. Got it home and loaded the DJI assistant 2 software on my PC. I noticed that the drone firmware was 2 versions old. I updated the firmware and this is when the problems started. I keep getting forward vision sensor and downward vision sensor errors. This doesn’t happen always but certainly 95% of the time. I’ve recalibrated the sensors I don’t know how many times but to no avail. I’ve even rolled back the firmware but can only go back one version, not to the original one though. While the fault is present, I noticed that the firmware version is “unknown “, when the fault is clear it reports the correct version. I’ve tried all sequences of starting up but to no avail. I sometimes get everything working ok but this involves turning the controller off and back on again in flight, a method I’m not happy about and not one that works every time. Any help will earn my undying gratitude