if in a chrome OS coreboot tree the coreboot.org tree is added as another remote, the state of the tree when switching to a branch tracked on the coreboot.org is incorrect:

vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
> git checkout -b upstr --track upstream/master
M	3rdparty/blobs
Branch 'upstr' set up to track remote branch 'master' from 'upstream'.
Switched to a new branch 'upstr'
es^o: projects/1grepo/src/third_party/coreboot 225 > git status
On branch upstr
Your branch is up to date with 'upstream/master'.

Changes not staged for commit:
  (use "git add <file>..." to update what will be committed)
  (use "git checkout -- <file>..." to discard changes in working directory)

	modified:   3rdparty/blobs (new commits)

no changes added to commit (use "git add" and/or "git commit -a")
es^o: projects/1grepo/src/third_party/coreboot 226 > git reset --hard HEAD               
HEAD is now at e2ae01a15e drivers/i2c/tpm/cr50: Simplify and increase init delay to 30 seconds
es^o: projects/1grepo/src/third_party/coreboot 229 > git status
On branch upstr
Your branch is up to date with 'upstream/master'.

Changes not staged for commit:
  (use "git add <file>..." to update what will be committed)
  (use "git checkout -- <file>..." to discard changes in working directory)

	modified:   3rdparty/blobs (new commits)

no changes added to commit (use "git add" and/or "git commit -a")
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

for some reason the 3rdparty/blobs directory is always marked as 'modified'. This is a bit more than a mere nuisance: when the tree is in this case it is impossible to use git rebase for rearranging the patch order, git reports an error:

error: cannot rebase: You have unstaged changes.