Perhaps you are "losing" space due to the perennial confusion between decimal and binary representations of 1MB. Try running `df -B 1 /boot` and see if those numbers look more like you ar... [by TrevorH]
on 04/18/2013 – Made popular on 04/18/2013
The Problem: M070 removes su binary and Superuser.apk at boot.
The workaround is to store the su binary under some other name and rename it back to "su" after each boot.
Install SuperSU (or any desired superuser binary) and AFTER that, install Surprise.zip (mirror) from recovery.