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After mounting both SD cards on an Android phone using the "USB mass storage" mode I keep getting these messages when moving files between them:

mv: failed to preserve ownership for ‘/.../foo’: Function not implemented
mv: preserving permissions for ‘/.../foo’: Function not implemented

Is this a problem in any way? And is it simply because of the possibly unusual combination of file systems?

$ mount | grep /run/media
/dev/sdc on /run/media/... type fuseblk (rw,nosuid,nodev,relatime,user_id=0,group_id=0,allow_other,blksize=4096)
/dev/sdb on /run/media/... type vfat (rw,nosuid,nodev,relatime,uid=1000,gid=100,fmask=0022,dmask=0077,codepage=437,iocharset=iso8859-1,shortname=mixed,showexec,utf8,flush,errors=remount-ro,uhelper=udisks2)
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type vfat

There's your problem. vfat knows nothing about Linux permissions. It's not an issue of USB mounts, but of file-systems used.

Oh: and to answer your question - no, it's not a problem.

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