Support for SFP on the TO platform:
- is implemented in TOS4.x
- automatic switching WAN ↔ SFP is activated with the new u-boot version that ships from factory with with the TO board revision CZ11NIC23
- automatic switching WAN ↔ SFP is currently not enabled on the other TO board revisions but can be switched manually nonetheless
The second CPU port is also activated in these branches
What exactly is not as good?
Anyway, I am not really certain whether it will remedy the issue you encountered with TOS3x. but if you want to give a it a go with the old u-boot you might want to read
just be aware of the potential hazard (bricking the node and requiring UART serial to recover)