How to reinstall an update

Just got my Vero 4K, I updated and got a sad face. I’ve been getting black screen’s ever since. How can i reinstall the update via putty since its not reading my usb on boot.

I am now getting a waiting for root filesystem device /dev/vero-nand/root black screen on boot everytime

See A reinstallation is the best way.
Some users had power loss during updates recently which caused some update issues.