TL-WR1043ND won't connect to CM600

I have a tplink_tl-wr1043nd-v1 and it won't connect it to a Netgear CM600 cable modem.

I tried OpenWRT 21.02.1 & 19.07.8

The "WAN" light lights up (on the modem & the wr1043nd), but it never gets any "link up" messages in dmesg, and it never gets any DHCP client messages in the log.

The wr1043nd works fine w/ other modems. The CM600 works fine w/ other clients (eg : laptop, apple tv).

What could cause this ? Is there any fix ?

Thanks !