Not booting after December update

Hello.

I have just tried the ALT F2, without effect.

I’m on the spash screen… and the only things that tend to prove my RPI2 is not stuck is that I can switch num lock on or off. that’s little…

I tried to open my microsd card in another linux computer and there was an error on the windows partition where vmlinuz is put.(the 255MB one)
No log present on the /var/log directory on the second partition.

Pierre