No-no-no, thank you!
I also tried the usbnet on boot after new hotfix, it seems it is the same issue.
All observations:
1) Kindle is up, usbnet active (no usbms), I can connect either by cable or Wi-Fi, all good.
2) I connect the cable, test usbnet again, then long-press the power button and hit restart.
3) Screen with "Your Kindle is restarting" sohws up. Then, usbnet turns off, for a brief 10-15 seconds I see the Kindle drive show up on the screen of my PC. I don't have enough time to safely eject it - since Kindle continues with the restart.
4) Then, after seemingly regular amount of time, Kindle boots into this semi-debug mode with "Collecting info". Meanwhile it still shows only 1/3 strings that usbnet reports.
5) Cable usbnet refuses the connection. Didn't try Wi-Fi yet.
Is this how it usualy goes when you restart a Kindle with Enable usbnet on boot? I mean, things in Step 3.