main: Switching mounts in Settings causes it to crash due to i2c error reading the IMU?

[TakKanekoGit]

Issue on main (6f2ef6f) 26 April 2026.

This doesn't seem to get triggered if I start the PiFinder fresh from the powered off state. It shows up if I run the PiFinder from the command line. Going into Settings and changing the mount type triggers the error.

Error log:

Process IMU:
Traceback (most recent call last):
  File "/usr/lib/python3.9/multiprocessing/process.py", line 315, in _bootstrap
    self.run()
  File "/usr/lib/python3.9/multiprocessing/process.py", line 108, in run
    self._target(*self._args, **self._kwargs)
  File "/home/pifinder/PiFinder/python/PiFinder/imu_pi.py", line 177, in imu_monitor
    imu.update()
  File "/home/pifinder/PiFinder/python/PiFinder/imu_pi.py", line 73, in update
    self.calibration = self.sensor.calibration_status[1]
  File "/usr/local/lib/python3.9/dist-packages/adafruit_bno055.py", line 369, in calibration_status
    calibration_data = self._read_register(_CALIBRATION_REGISTER)
  File "/usr/local/lib/python3.9/dist-packages/adafruit_bno055.py", line 828, in _read_register
    i2c.write_then_readinto(self.buffer, self.buffer, out_end=1, in_start=1)
  File "/usr/local/lib/python3.9/dist-packages/adafruit_bus_device/i2c_device.py", line 135, in write_then_readinto
    self.i2c.writeto_then_readfrom(
  File "/usr/local/lib/python3.9/dist-packages/busio.py", line 192, in writeto_then_readfrom
    return self._i2c.writeto_then_readfrom(
  File "/usr/local/lib/python3.9/dist-packages/adafruit_blinka/microcontroller/generic_linux/i2c.py", line 90, in writeto_then_readfrom
    readin = self._i2c_bus.read_i2c_block_data(
  File "/usr/local/lib/python3.9/dist-packages/Adafruit_PureIO/smbus.py", line 264, in read_i2c_block_data
    ioctl(self._device.fileno(), I2C_RDWR, request)
OSError: [Errno 121] Remote I/O error

[jscheidtmann]

Did you stop the PiFinder service first, before invoking it from command line? sudo systemctl stop pifinder?