Okay so if I understand well you're actually running your SP2 with the March update without any issues ?
Okay so what I should do is creating a bootable USB before doing anything on the SP2, then update.
But do the March Firmware is really necessary ? I'm pretty sure this thing destroyed my SP2.
Actually I'm not running the March firmware.
I installed it but as I had problems with wireless connectivity with my TV, I reversed the process through a cloning ssd I had done before installing the March firmware.
Currently I have in my windows update, the option to install the March firmware. But I refuse to do it.
I have all other updates installed.