Background: Last January I wanted to mount an ext4 formated SD card, and it turned out to be a bit more difficult than just inserting it in my Note II. Back then, there was no exFAT support whatsoever in AOSP ROMs and I wanted to be able to run either TouchWiz or AOSP without having to reformat my card. FAT32 wasn't an option because of the 4GB limit.
I've since automated the methods that were devised in my previous thread (with due credit to @ttabbal), and since they should work on a variety of devices running TouchWiz ROMs, I thought it would be best to create a new thread in a more general location.
The usual caveats apply.
- TouchWiz ROM
- init.d support
- a custom recovery that mounts ext4 SD cards properly, or a mounting updater-script. TWRP works out-of-the-box on my Note II.
[MOD]Term-init & Zip-init: Enable Init.d for Any Phones w/o Need of Custom Kernels!!!
SD card removal:
Should you need to remove the card it can be unmounted and safely removed from the storage settings as usual. Mounting it again requires either a reboot or manually executing the init.d script and then activating the card in the storage settings.
The mounting occurs early enough during the boot process that the media scanner and MTP services have no issues with this.
If your init.d support comes from the install-recovery.sh trick, CWM will prompt to delete the script before reboot. Don't.
If the mounting script doesn't run for some reason, or you try to activate the card before having mounted it manually, the phone will give an error and ask if you want to format the card. Don't.