Après avoir googler pour trouver la solution à :

remote: Counting objects: 321, done.
error: pack-objects died of signal 928/251)   
error: git upload-pack: git-pack-objects died with error.
fatal: git upload-pack: aborting due to possible repository corruption on the remote side.
remote: aborting due to possible repository corruption on the remote side.
fatal: protocol error: bad pack header

Il s'avère que les outils classiques sont :

git gc
git fsck
git repack

Si rien n'y fait, tenter :

git config --global pack.windowMemory "100m"
git config --global pack.SizeLimit "100m" 
git config --global pack.threads "1"

Si toujours rien n'y fait (solution fournie par Linux Torvalds)

rm -Rf .git/logs/
$ git gc