I updated my rooted Sony PRS T1 from firmware 1.0.03.11140 to 1.0.04.12210 and run into the problem that I do not have a rooted device afterwards. I tried to flash root again with minimal-root.zip
but it does not work.
I looked around and see the reason: After flashing to 1.0.04.12210 there are no space left on system partition for superuser.apk.
Before the firmware update I have a fully functional rooted reader with a second ext3-partition for apps on the external sdcard (made with Link2sd as shown here: Enlarge Storage for apps
Here is my way to solve this situation:
1. Make full backup of all partitions before updating the firmware (just in case...) How do I do a full dump
2. Update to Firmware 1.0.04.12210 as written on Sony Site
3. After the update connect the reader via usb to pc, extract Superuser.apk and su from "minimal-root.zip"-Package and copy both to the root-folder of the sd-card named READER
4. unmount and disconnect reader from windows
5. Reboot in Recovery mode: Howto enter recovery mode
6. connect reader to pc and make a terminal connection via putty and login with user "root" and no password
7. do the following:
# mount system-partition
mount -t auto /dev/mmcblk2p10 /tmp/sys
# Look, theres no space left ;-)
# delete unused Wallpapers to get free space
# check free space again
# mount reader-partition
mount -t auto /dev/mmcblk2p4 /tmp/reader
# copy superuser app to system
cp /tmp/reader/Superuser.apk /tmp/sys/app
cp /tmp/reader/su /tmp/sys/bin
# make correct settings (get infos from do_update.sh in minimal-root.zip)
chmod 06755 /tmp/sys/bin/su
mkdir -p /tmp/sys/xbin
ln -fs /system/bin/su /tmp/sys/xbin/su
# sync, unmount and reboot
8. After reboot start awd launcher (via "Bar Shortcuts") and start "Link2SD"
Now you can say "okay" to superuser permissions then choose "ext3" as type for second partition of the external sdcard. The mount script for the Link2-SD-Partition will be created new.
9. reboot reader
Now all apps, data & root are available again!!!
Only issue is to say "okay" again to every first access to superuser rights from an app.
I hope this helps somone else.