Guys,
I just want to let you to know. It's possible to workaround the WAN port dies problem by exchanging the roles of WAN and LAN ports. I.e. all 4 ports will become WAN, and WAN port will become LAN.
This requires several changes in the nvram, so I do not want to verify this on my unit. :D
This is very delicate operation. So, if anyone is interested in this, then let me know.