This "update.zip" style installer simply automates the process of modifying /system/etc/permissions/platform.xml to make the tablet permissions act the same as previous versions of android.
In particular, programs with the WRITE_EXTERNAL_STORAGE permission will be able to write to the removable storage card. (Honeycomb changes this to require WRITE_MEDIA_STORAGE which very few, if any, 3rd party programs use.)
If you are having issues with programs writing to your storage card, this might fix it.
This uses 'sed' to make the edits. If this is installed twice, it won't re-modifying the file. (However, if you have manually edited the platform.xml file, and then run this script, it might make create duplicate, but harmless, <group> entries. Before making the modification to platform.xml, it will create a backup of the file (called platform.xml.backup) in the /system/etc/permissions directory (if the backup doesn't already exist.)
Download the file, and place on your sdcard. Reboot into recovery and install .zip from sdcard. Choose this file. Done..
(I've tested this with my CWM based recovery and it works. It _should_ work with the factory recovery as well, but I haven't tested... Please reply with your results.)
None. If you aren't familiar with using recovery to install updates, you should research the topic before continuing.
If you are curious, here is the sed command I'm sending, using busybox compiled from the cyanogenmod sources:
sed -e '/WRITE_EXTERNAL_STORAGE" >$/N;s/\n\(\([ \t]*\)<group gid="sdcard_rw".*$\)/\n\2<group gid="media_rw" \/>\n\1/' -i /system/etc/permissions/platform.xml
(I'm not fluent with sed, so if someone knows a better way to do that, please feel free to educate me.)
File is attached below...
UPDATED Feb 5th, 2012: the script will change the filesystem permissions of the platform.xml file before attempting to edit it. This MAY overcome issues people have been having with non-rooted devices, but I'm unable to test so I don't know. Okay, well, it appears that this won't work for a device that doesn't have CWM Recovery installed. Not sure why, but at least I've repeated it.