[poroto123]

Hi. Sorry for my english, but i'll try to expose my case:
I have an Kindle 7. Everything ok until a few months ago. The reader started with many problems: battery charge begun to last only a couple of hours; and then, the main problem, is that the software started to fail very often. When i'm reading a book sometimes get error and i have to restart (pressing button 40 seconds); when the system back, the reading % returns to previous %; and now i cant charge any book. I've try with calibre and manually, and nothing. With any reset, the new book disappears. The firmware is 5.11.11. Surely the problem is related to the update. I download the last firmware (5.12), copy/paste, update, but, at the end, the problem continue: books are all there, the firmware remains the same (5.11), and nothing has changed. The same with factory reset: make the process, but the system has not changed. Indeed i tried to downgrade to 5.3 and another firmware: copy/paste, update, but the problem remains.
I contacted with amazon (japan, the device came from there), and suggested me update to 5.12. I told them that i had done it, and at the end they give no solution.
After all: how can i solve this trouble? I think something is blocking the system and not allows to make a factory reset or an update/downgrade. How can i unlock it? Is there any system archive that i can modify? My intention is to make a factory reset, but i can't while the system stay locked. (In the root, there are many archives: *.calibre; bootlex.log; some screenshots: i try to deleted it, but returns with the reset).
Please help me with this issue!!!

Greetings and thank you so much