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Investigate: Sdcards with no UUID #231
There is currently a single case on a LG G3 where SD Maid can not get access to the external sdcard on Android 5.0 through the Lollipop storage framework.
Currently it looks like that sdcard returns no UUID from
As other LG G3 devices do not experience this issue, it is mostlikely not SD Maid at fault but an issue with the sdcard. The UUID value is used for unique identification, to lookup reverse uri<>path mappings and to sort out duplicate storage entries.
While the code could be made to work without the UUID it is unclear what possible pitfalls this opens so this is basically not something that we could just try.
SD Maids volume mapping code is inspired by the ExternalStorageProvider which also rejects volumes without an UUID.
It's unclear how to further proceed here or if at all.
I'm still investigating an issue where the system has no UUID value for an external sdcard, which makes it impossible for SD Maid to restore "normal" access to the external sdcard on unrooted devices with 5.0+.
I've attached two screenshots of the current stats i got, the LG G3 seems to be certainly a canidate and some Samsung devices.
An example output for an LG G3 device is:
Both times, no UUID, normally the value is set and something like "C7BA-FD11".
To provide access on Android 5.0+, SD Maid needs to reverse map the URIs it gets from the system uris to actual files/pathes.
Normally "foobar" is the UUID of the storage in question.
But now we have storages without a UUID. The only case i could look at in details (LG G3) had the mount name, e.g. "extSdCard", for "foorbar" where normally the UUID is used. This seems very arbitrary.
where i got my inspiration, they even use the same approach.
Seems to common on CyanogenMod builds, but not exclusively.
Here extSdCard was part of the voluem list but didn't return an UUID.
Another intresting case, we have a UUID-Permission match for the external sdcard but are looking for an additional entry, possibly an USB OTG device? The mount list didn't show any though. S5 (LRX21T.G900FXXU1BOJ1):