How to reset ME-C JTAG to its initial state?

I want to reset my ME-C JTAG to its initial state,
better, I want it to behave as ME-C without JTAG
to test my download procedure of the modules without JTAG.

I put the naftpapp example in the debugger, ran it,
ftp’ed a bootloader rom.bin, quit ftp.

I’m not sure whether this bootloader is the correct one
neither if it is really flashed.

I detached the debugger, reset module.

There are some DHCP Discovery messages and Boot Request
messages, but I don’t know how to contact the -C JTAG
again.

I use NET+OS 6.0e.