In the machine you want to connect to the embedded Linux box, set the ip to be 10.10.10.1 and subnet 255.255.0.0. There is nothing wrong with the IP of the embedded, but subnet mask is wrong. The subnet mask should only be used to decide if a packet should be sent to default gateway. To prevent it from that your connecting machine must be in the scope of the embedded's subnet mask.
On the other hand, as the ip/mask is an impossible combination, can it be that your settings were not accepted which means it went back to its older setting? Are you sure you can't reach it with another protocol than IP? Just some suggestions from the top of my head.