Sorry, me again....
The backdoor lock looks to be working, but when I checked the update state the screen didn't refresh properly after pressing the menu button twice. It refreshed well enough to be able to restart from the menu, which restored normal function. So not a big problem, but I thought you should know about it. Serial number B01D x running 5.3.3.
BTW, is it supposed to overwrite the item I already had in the KUAL (launch collections manager)?
Not very good at moving electrons, please forgive innate stupidity, and thanks for the work you have put in to this.
https://www2.mobileread.com/i/smiliestext/thankyou.gif