If your connected SQM experiences a problem after a firmware upload, the unit might be easily recovered back to an operational state.
The firmware upload only writes to the "program" area of the unit. The bootload area, calibration data and serial number are untouched.
For the first 3 seconds after power-up, the unit is waiting for a firmware upload.
You should be able to reload the original firmware as follows:
- Start up the latest UDM software which you can get from here: http://unihedron.com/projects/darksky/cd/
- Press "Find", your SQM should be displayed in the Found-devices window. If no device shows up in the found list, then there is another problem which cannot be fixed by this procedure.
- UDM may try to read from the device and fail, don't worry about that for now.
- Go to the firmware Tab, and "Select Firmware" then choose the appropriate firmware for your device. You may have to also select "All Firmware" at the bottom right of the "Open Existing File" dialog since it might automatically be showing other types. Select the desired firmware for your unit (note that SQM-LE files are also used for the SQM-LU).
Do not press the Load button yet. - Unplug the SQM then plug it back in then press the "Load Firmware" button within 1-2 seconds. If the progress bar starts incrementing, then the meter will work fine, otherwise there is likely a hardware issue that needs repair.
- The firmware should completely load. After the progress bar as completed then press "Find" in UDM to re-find the meter.
