[[!comment format=mdwn
 username="joey"
 subject="""comment 1"""
 date="2016-03-07T16:58:35Z"
 content="""
I replicated this as best I could, and the dropunused succeeded. But my
strace has an extra chmod:

	stat("./annex/objects/02e/a64/SHA256E-s30--b6eac296ebeab4b5593387489571654cd5019d8bb3bc3bc08ac8a41e22bad133/SHA256E-s30--b6eac296ebeab4b5593387489571654cd5019d8bb3bc3bc08ac8a41e22bad133", {st_mode=S_IFREG|0444, st_size=30, ...}) = 0
	stat("./annex/objects/02e/a64/SHA256E-s30--b6eac296ebeab4b5593387489571654cd5019d8bb3bc3bc08ac8a41e22bad133/SHA256E-s30--b6eac296ebeab4b5593387489571654cd5019d8bb3bc3bc08ac8a41e22bad133", {st_mode=S_IFREG|0444, st_size=30, ...}) = 0
	chmod("./annex/objects/02e/a64/SHA256E-s30--b6eac296ebeab4b5593387489571654cd5019d8bb3bc3bc08ac8a41e22bad133/SHA256E-s30--b6eac296ebeab4b5593387489571654cd5019d8bb3bc3bc08ac8a41e22bad133", 0100644) = 0
	open("./annex/objects/02e/a64/SHA256E-s30--b6eac296ebeab4b5593387489571654cd5019d8bb3bc3bc08ac8a41e22bad133/SHA256E-s30--b6eac296ebeab4b5593387489571654cd5019d8bb3bc3bc08ac8a41e22bad133", O_RDWR) = 16

So, it kind of looks like it checked the permissions and decided 0444 was good
enough and didn't chmod it to allow write (in order to lock it for removal).

The only way I can see how that could perhaps happen is if git-anenx thinks
it's in a crippled filesystem that doesn't support chmod. But then the file
shouldn't be locked down like that. I was, though, able to reproduce 
that behavior after running `git config annex.crippledfilesystem true`

So, I need more information: What filesystem is the USB drive formatted with,
and can you run `git config --list` in the git repository on the drive and
paste the output please.
"""]]