Hi
A year ago I purchased a Sony DPT-RP1 ebook reader on ebay.
Actually I thought it had a stock firmware without any "hacks" etc.
But upon receiving it, I noticed it had an unblocked Play Store and had the ability to install new apps.
It has stock firmware 1.4.02.09061.
Now I want to update it, but cannot (it gives me error: Unable to update. Error code: 900001).
I guess this is because it has special firmware by GoodeReader.
Is this possible to update at all?
How can I totally reset it to the stock firmware without any "hacks" and playStore?