For those inpatient I'm gonna get straight to the point - yes, the black level was restored to original state after the EEPROM write.
Now the full story:
back in 2010 as I was about to buy G10 I found this thread started by Orta so I already knew about the rising blacks before I actually bought the TV (I gave it a lot of thought and decided to buy it anyways since it was not clear back then if it was affecting all the sets or Panasonic will release a FW fix). Therefore I decided to take a picture every couple of hundred hours of the screen in the darkness with the same exact settings with my camera on full manual (aperture, shutter, ISO, WB, focus, etc.). The first rise I experienced between 232 and 295 hours, second between 942 and 994 hours, and third (final?) between 2176 and 2326 hours.
Just before I started fiddling with the EEPROM I took another picture at 5263h for direct comparison and the last one tonight at 5265 hours. I'll post here only the first one at 5h and the last two (they're ~2MB each) so you can see and comment but from what I can say the black level is about the same at 5h as at 5265h after the panel reset.
I tried to decipher how the panel age is stored in the EEPROM but gave up after some 15 minutes as it is not obvious. The only thing I found out is that the 6th and 7th byte represent on/off hours.
Here is the reading from second to seventh byte: 13 c5 47 88 11 4a
TV represents those bytes as 5264:00h and 4426 (11 4a) on/off cycles. From what I tell the counter for hours was incrementing in 15mins steps, because I never saw on that counter (when you go through service menu to check panel hours) anything else besides xx:00h, xx:15h, xx:30h and xx:45h. There are a few minutes between the reading and checking through service menu so the last few bits might have changed in between. Since I did not reset the counter in peaks EEPROM, I still get the actual hours and on/off times from the service menu, but if I check the panel EEPROM, I see that it's counting from zero, again (which now makes it difficult to check the EEPROM bytes with what's on the screen and decipher where/how is the panel age stored).
I am planning creating a dedicated web page with step-by-step easy to follow instructions so everybody can fix their black level on G10 (hopefully there'll be an easier method for S10 and somebody can try it at V10 or G13 models as well) for some $10-15 and a bit of spare time so I'll keep you posted in a few days.
Edit: just to be clear, the guide will be free for everybody, you'll just need to get yourself an Arduino board (which is about $10-15 on eBay if you don't have any, yet).Edited by mironto - 7/8/13 at 12:32am