Originally Posted by ebmr
Well, booting an update image from OS Firmware/files on the SD card doesn't seem to be a function of the stock reader at all then? This would be an easy way to gain access, but obviously it's provided by some rooting package?
Booting an update image from SD card is a stock feature. However, in the early (U.S., Euro, Japanese) releases of the PRS-T1 the SD card boot was available from an unsigned image, while in the later releases of PRS-T1 (Russia and Japanese PRS-G1) the boot from SD cards required a signed
image. Since the image is signed with a private key, the only way to enable loading unsigned custom images would be via a change to the recovery mode script that loads the image.
Everything locks into ability to read and write files and MTD blocks on the Reader. I have not been able to establish such ability in the PRS-T2, so there is not much else I can do.