Set the NIC to static IP of 192.168.1.1
Connect the ethernet cable to any port
Connect USB/TTL cable as shown:
All files needed to be installed can found in this .zip file
putty.exe
tftpd32.exe
EA8500-factory-to-ddwrt.img
EUPL-EN.pdf
tftpd32.chm
tftpd32.ini