nnrpi1 is now back in S4 with a new SD card and new raspberry pi.
The freezing originally continued (it was the USB system failing) but was fixed with a change to /boot/cmdline.txt coherent_pool=4M
It seems the kernel update to fix one bug introduced another... 
Now it is running again with all TTYs connected. I think one TTY may not be working but 11 should be