ok, that makes sense then
The only reason I went into DIAG mode was because I could no longer get into USBNet using the normal route. When I first installed it, everything worked fine and I could log in with my password. After the upgrade to 5.3.6 is when I started having trouble.
I'm guessing the new firmware has a new root password. Perhaps the old password generators for the KT and K4 still work for the PaperWhite. I'll go try that now.
Thanks!