Hey Guys,
I came across the same problem, where my reader (I have the T3) would be on a constant loop and get stuck on "opening book" I tried soft reset, hard reset was not possible and sometimes the screen would respond. When it did respond, I check the battery charge and was showing 100%.
I was VERY frustrated to the point I was going to get a new battery online....
so I decided to pop open the unit. Before I played around with the battery (which btw, is soldered into the MB) I decided to press the ON button without the case around it.
And lo and behold...it came to life without any issues. I did a HARD reset (finally) and no problems. THen I loaded the new firmware (the Kobo one) and everything was happiness....
...until I placed the case back.
SAME ISSUE! The unit started looping. I came to realize it COULD not be the firmware nor the battery. It must be something else, something I missed. Maybe I touched something in the back that created a grounding? SO I went for the easy way: removed the case cover (again) and press power.
That was it: reader back to life.
Hmm....something to do with the power button then. But what?
I decided to replicate the problem, this time without the case in. So how did I do it? I pressed and held the power button down and it started looping, like the original problem. SOmehow, the plastic portion of the power button of the casing must be providing a gentle 'push' to the actual power button on the MB of the reader, creating perhaps the loop?. ANyway, I have removed the plastic power button on the casing and placed a small piece of electrical tape (the black kind) to prevent dust (most of the time, the reader goes to sleep mode anyway.
That was IT!
I was two hours trying to work on this, since I noticed the problem last week but just got around to work on it now. Sigh. I was sad I had to let go this reader since it was a xmas present from my parents but now that is back, i get to catch on much of my reading.
Hopefully this trick will work out for you too.
-Miguel