Please follow the below procedure.
root@:RE:0% mount -u -o rw /
root@:RE:0% ls -l /boot/ffp.cookie+
root@:RE:0% ls -l /boot
root@:RE:0% rm /boot/ffp.cookie+
root@:RE:0% ls -l /boot/ffp.cookie+
ls: /boot/ffp.cookie+: No such file or directory
root@:RE:0% ls -l /boot
root@:RE:0% ls -l /boot/ffp.cookie+
ls: /boot/ffp.cookie+: No such file or directory
root@:RE:0% mount -u -o ro /
root@:RE:0% exit
exit
{master:0}[edit]
TEST# commit
configuration check succeeds
commit complete