Suddenly my USB sticks all got write protected (after W 10 update) !!

"After a recent Windows 10 update, suddenly my USB refused to write anything on it.
Could not even Format it. Diskpart went through the steps and said the write protect was now removed.
Nope, Diskpart would not accept the "clean" command immediately following, saying USB was write-protected.

I tried everything, from Diskpart to Registry tweaks. Also tried booting in safe mode. Nothing worked. So decided the USB stick was just worn out from many write cycles. I tossed into the garbage can. Next, I placed a new USB stick in the computer, and surprise surprise it was write protected as well. Then I knew it was something messed up in Windows system from recent update. I tried the new USB in my wife’s computer and it worked fine. So as a last resort, executed the "recovery" procedure. (from Settings-->Update&Recovery-->Recovery). That installed a fresh copy of Windows from the Cloud. Did not need any other hardware for the install. Did not need to re-activate windows. The procedure was pretty good actually, even giving a desktop icon to list Apps removed by the procedure. Pretty painless but slow with a couple of boots required during the procedure.

Voila, I could now write on the new USB stick. So retrieved the USB discarded from garbage can and it formatted just fine, but this time I used the NTSF format just for kicks, instead of the FAT or FAT32 format. No more write protected disk on any USB sticks now. Using Windows 10 Home, Version 20H2 , OS build 19042.746

Did you find out what update caused this to happen?

Try resetting your BIOS to default save/exit/reboot. If that doesn't work, try uninstalling your chipset driver and reinstalling new/current driver.