NAPS2 is a scanning software that includes drivers for a large variety of scanners through the use of its SANE (Scanner Access Now Easy) back-end. One of the scanners supported is the Plustek OpticSlim M12, a scanner that I have. Though, to use it, I had to manually edit the NAPS2-provided gt68xx.conf configuration file to provide a path to the firmware, and the USB vendor and product IDs.
The USB firmware, which is uploaded to the scanner, is available in the Windows (and macOS?) driver, which is thankfully still available on Plustek's website, here. If it isn't available anymore, I will upload a copy here 1). I believe that I found it in the CAB file, using cabextract. 2)
As I am using NAPS2 on macOS, I decided to directly modify the NAPS2.app package (“View Package Contents” menu option) to add the required firmware file and configuration changes. I edited the configuration file under Contents/Resources/_config/sane to add the following (the usb declaration might have already been there):
- gt68xx.conf
usb 0x07b3 0x0412 firmware "/Applications/NAPS2.app/Contents/Resources/_config/sane/cism216.fw"
Finally, after editing the NAPS2.app package, open NAPS2, and after adding a profile using the “SANE Driver”, the scanner should work! Make sure to adjust the resolution (dpi) and page size to have a proper scanning speed. Note that I noticed that the scanning result might be sheared at some resolutions, so some experimentation might be needed. Greyscale and colour scanning works fine at 300 dpi (pretty fast) and 600 dpi (very slow).
Note that all of these steps have been done in May 2024, and under macOS Big Sur. In addition, Linux has been used for extracting the CAB archive.