I can no longer SSH into a machine that I have a wired connection to. How can I get back in?

Solution 1:

So it was very silly but subtle. After I shared internet with the board and ran dhcpcd, I set the IP address of the USB Ethernet connection back to manual mode and set the address to 169.254.132.152...which was the same as the board I was trying to SSH into. Rookie mistake. It needs to be a different address in a way that would be the same after masking with the net mask... for example 169.254.132.150. Then we are on the same mask but not hogging the same address. This explains why I could ping, and why it would not accept my "password" because I was ssh-ing into my connection...not my board.

Tip: When you change the IP address of the connection, make sure you unplug your USB and plug it back in so it will update.