I have the similar issues with USB detection after upgrade to Ubuntu 20.04 on my scanners (HP Laser MFP 135a - smfp backend and HP OfficeJet 4630 - hpaio backend).
WIth
The hpaio scanner is detected on USB, but it is not able to communicate (xsane, scanimage, simple-scan). Only scanning by network is working correctly.
With HP Laser MFP 135a - smfp, it is not able to detect it on usb port.
I would like to investigate this issue further.
How did you enabled logs to investigate this issue?
I have the similar issues with USB detection after upgrade to Ubuntu 20.04 on my scanners (HP Laser MFP 135a - smfp backend and HP OfficeJet 4630 - hpaio backend).
WIth
The hpaio scanner is detected on USB, but it is not able to communicate (xsane, scanimage, simple-scan). Only scanning by network is working correctly.
With HP Laser MFP 135a - smfp, it is not able to detect it on usb port.
I would like to investigate this issue further.
How did you enabled logs to investigate this issue?