Is bridge mode really passthru?

Bridge mode should basically be passthrough, so the Helix itself shouldn’t be blocking your FTP. I’d double-check if it’s really bridged (your router should be getting a public IP) and then look at your router’s port forwarding/firewall rules. Sometimes after switching equipment, the internal IPs change, so the old port forward won’t work until it’s updated. Also, if you’re using passive FTP, make sure the whole passive port range is open, not just port 21. Most likely it’s a config on your router rather than the Helix blocking it.