This is serious, but also kinda funny as it happened to me also..
I fell asleep while flashing!
It seems the TP2 does not like to be connected for so long after a task29 flash.
The battery is not the issue as both my batteries were fully charged and it still charges when plugged in.
Just swapping batteries didn't work either, and I had battery left out for almost a minute while changing..
The solution for me was to disconnect the device from laptop, AND take out battery...
FOR A WHILE (more than just a few minutes) LEAVE UNIT alone WITHOUT BATTERY!!
I can't tell you just how long, because it was nightime, and I fell asleep again! lol.
Anyway after I put battery back in, it came alive as it was rebooting, I just pressed buttons to put in bootloader..
And flashed from memcard..
EDIT:
It's a good idea to always have a good custom rom (named "RHODIMG.nbh") in root directory of your memcard in case U need to flash back to a safe rom.