$ git clone -n https://src.fedoraproject.org/rpms/iscan-firmware.git /var/lib/mock/f41-build-side-1-3126971-39530/root/chroot_tmpdir/scmroot/iscan-firmware
Cloning into '/var/lib/mock/f41-build-side-1-3126971-39530/root/chroot_tmpdir/scmroot/iscan-firmware'...
$ git fetch origin 608e232d97a4188eb4de23d86a07dffaaf8a5027:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/iscan-firmware
 * [new ref]         608e232d97a4188eb4de23d86a07dffaaf8a5027 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 608e232 Update and clean up