I tried to create a symbolic link on the "internal SD card" of my Galaxy SD2. It failed with "permission denied" and I quickly realized this file system is vfat.

How can I reformat /storage/sdcard0 with a modern file system instead, like ext4?

Are there any drawbacks if I do this?

  • What OS you are using on your PC (or wherever you might want to mount that card), and is your device using MTP or UMS? There might be compatibility issues when other devices come into play. As long as your device supports ext4, there is no issue from that side I could think of.
    – Izzy
    Feb 14, 2013 at 14:07
  • @Izzy Good point. I am mostly MacOS and Windows, sometimes Linux. On Windows, I usually do not mount the USB but use MTP instead (because precisely, it avoids unmounting the SD card in Android)
    – rds
    Feb 14, 2013 at 14:33
  • I see no problems when one can be sure Windows is never involved (or just with MTP). But also keep in mind you might have to mount a card directly e.g. for "troubleshooting" (something broke and you can't mount it via MTP/UMS anymore). If you sell your device, that's another thing: the buyer will not need your data, so you either sell it without/with a different card, or simply re-format it. -- I will sum this up as an answer.
    – Izzy
    Feb 14, 2013 at 15:27

1 Answer 1


Possible drawbacks

As for the "drawbacks" part, there are different things to consider:

  • Windows cannot read ext4
  • Mac/Linux/*nix should have no trouble with it
  • Using MTP, Windows won't have any trouble either
  • If your ROM supports ext4, there should be no local problem
  • You might want to switch to a different ROM one day -- that ROM might not support ext4 (unlikely, but not impossible)

There are several situations to consider, as well:

  • If you one day get trouble with your card which cannot be solved "locally" (e.g. the card no longer mounts locally, or cannot be mounted via MTP/UMS, or you need to do a recovery of accidentally deleted files), you might need to attach it to your PC using a card reader (ext4 ↔ Windows: Fail!)
  • If you lend your device to somebody only having Windows, he might encounter problems
  • If you one day sell your device, you have to keep this in mind, too

Though for the last two situations, the solution might be simply to remove/replace the card, or re-format it (in the last case).

How to do it

Still here? OK, so the drawbacks seem to be negligible. There are multiple ways of how to get your card formatted with any file system:

  • Note that it's the internal sd card, so using a card reader is not an option. Formatting the SD card using the device terminal app assumes that this is an available command. forum.xda-developers.com/galaxy-s2/help/… indicates that this may in fact be difficult or impossible to do.
    – intuited
    Sep 8, 2014 at 18:39
  • True. I just tried to keep my answer a little more generic, so it applies to internal and external cards. For internal cards, the parts using a card-reader of course don't apply ;)
    – Izzy
    Sep 8, 2014 at 22:55

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