My touch with 2.6.1 became unresponsive today. Probably more books loaded onto SD card than that firmware version could handle. Factory reset and over write format of SD card got it working again. It could handle less than 1,200 books loaded onto SD card but with more than 2,000 books it was really slow. Also 6 Andy Adams public domain books downloaded from Feedbooks could not be read.
Message: They had DRM that adobe digital editions said did not match my password. This firmware version must have stability problems that shows over time and with excess books stressing database. Kobo forces update to this unstable firmware and will not update to the next firmware version. It is stuck in no mans land. Could the next firmware be worse? This is the entertaining Kobo serial mystery.
My Sony T1 can easily handle many more books than Kobo Touch.
I mainly use Kobo Mini with just a few books. Kobo Touch is ok with fewer books.