cannot install apps with having to reflash due to tablet failing

Just when you think everything was going so well, switched the tablet on today and the old boot loop appeared again, despite every effort made I was left with nothing but re-flashing again!! erased the nand a few times, level format and back to stock pipo and then after seeing it working flashed it back to the rileyrom 4.2
again this went smoothly,
Checked the log files and all seemed well, the format, no errors, or bad blocks showing

Left it running for a while, with a test app running which re-booted a few times and still all seemed well, that is until I tried to install some apps. Installed Gmail, facebook, taptalk, messenger, bbc news/weather and then after waiting for the installs to finish I shutdown waited a few mins and restarted, only to find that first off I was stuck in the rileyrom boot loop screen, on the second attempt I found that the apps failed to start with multiple errors, (acore,gapps,play) to name a few.

Basically I left with tablet which is only good for watching movies of my usb card, or browsing the internet, as every time I have tried to install an app it has led to me having to re-flash.

I'm guessing the nand memory is screwed, with no way of being able to repair it