No eggtimer after replacing screen

I broke the screen on my Pocketbook HD Touch (632), and replaced it with a new one. I then did a sync and it updated the firmware to U632.6.7.1706.

Everything works perfectly, much to my surprise, with just one exception. When I turn it on, instead of showing the eggtimer, it shows a blank screen alternating with a screen with the word 'Pocketbook' 6 times. Its a trivial problem really and doesn't affect anything else, but it would be nice to fix it (if only to stop my grandson saying "see - you should have bought a Kindle").

Anyone have any ideas? I'm guessing it is just a an image file gone missing, but have no experience with the software side of this device.

Thanks
Graham