Thanks for the suggestions. I am still at a loss. I tried various things and the following is a report:
1. swapped the USB cable and port with no difference in behaviour
2. The printer works on another machine with Ubuntu 14..04 with hplip
3. The printer works fine on the same machine (where i am having the problem) when I boot from a pendrive with ubuntu-mate 16.04.1.
4. I checked that HP1020 plus is fully supported in hplip.
5. I am able to add the printer through cups "system-config-printer". The printer utility shows 'unknown' device, 'A printer connected to a USB port'. After selecting the make, model and driver from menu, the printer is added successfully. But does not print test page. "journalctl -u cups -e" yields several error messages, the last of which are:
prnt/backend/hp.c 825: INFO: open device failed stat=12: hp:/usb/HP_LaserJet_1020?serial=S404LYD;
io/hpmud/musb.c 1151: unable to open hp:/usb/HP_LaserJet_1020?serial=S404LYD
6. Another thing I noticed was: if the printer is ON during fedora boot, there are several instances of
usb 1-2: device descriptor read/64, error -110
usb 1-2: device descriptor read/8, error -110
All the above observations pertain to the behaviour after today's dnf update which included kernel to 4.10.5
I appreciate any more suggestions to try. Hope to sort it out before trying a reinstal of fedora.