Has anyone found a way to re-configure the Topaz switch to un-bridge LAN0 and LAN1?
LAN0 and LAN1 are bridged only upon power on (or hard reset) of the board. When you load your OS they become separate interfaces having separate broadcast domains. A soft reboot does not return them to a bridged state. A hard reset (reset button) or a power cycle, does (until the OS loads).
So in the period between a board reset and full OS load, the interfaces are bridged. If the OS fails to boot for some reason, they will remain bridged.
It appears as if undoing this short-term bridging would require (a) the latest u-boot code, compiled and flashed into the unit, and (b) a Device Tree Blob (dtb) file which marks the interfaces as “disabled”, in a new bitmap mask field. This would ensure that from power on or reset until the OS completes the boot, the interfaces will remain disabled. I have not done that (yet), mainly out of concern of bricking the board 🙂
Hope this helps.
