Martineau
Part of the Furniture
Understand that USB mount is later than dnsmasq, but if I restart the dnsmasq service after USB is mounted, the tftp server should work properly right? But it still does not work after I restart the dnsmasq service.
Given that dnsmasq's tftp 'works' when using /jffs/pxe, and your configuration data is apparently too large to fit onto /jffs then I have no idea what is causing your particular tftp issue, as clearly we are agreed that tftp functionalty can and does actually work on these routers - just not with your large file.
Good luck