Trying to load v6.41

So evaluating this little box as a potential CPE (SFP cage) No console kind of a minus. Worked fine until it did not. Went through the process of trying to get netinstall to work on various machines to no avail and could not get netinstall to see the box. Finally took an old XP laptop and tried netinstall with a similar working RB2011UiAS-2HnD-IN and saw a mac address in netinstall the first try. So it seems it is a brick.

I took an old cisco 2940 and hairpinned the MikroTik and the laptop and wiresharked the traffic between them. (span) After holding the reset button down until the beep and capturing frames I see an exchange of TFTP traffic between the laptop and the MT boxes. Both routers register a mac address from the switches perspective. Both router's send TFTP packets with "bad" FCS checks according to Wireshark in the responses to the TFTP packet sent by the laptop/netinstall. The only difference is that the working machine shows up in the netinstall list and the one I am trying to get working does not.

So any theories? It appears that the netboot function is simply tftp so presumably that means the router boot function is working on the router as it is sending packets with the appropriate address as source to the appropriate destination. Both routers appear to be doing some munging of packets but that does not seem to matter. Don't see any significant difference in the packet captures. I guess I will throw it away but it drives me crazy not to know what happened. Hardware fail I presume but I cannot for the life of me explain why netinstall is not recognizing one machine that it is getting exactly the same TFTP packets from as a machine that works.