I would be very interested in this too, unfortunately my backplane (BPN-SAS2-826EL1) is at least two weeks away so I won't be able to research it myself. My guess is that the levels are 3.3V.
Yesterday I read found this too:
Super Micro Computer, Inc. - FAQ Entry and from what I understand it should mean that one can use AOC-USB2RJ45 with CBL-0165L to update the firmware, but I cannot find more information on this.
Interesting, thanks for the info. Please keep up posted when yours arrives. Peering into the case to look at the backplane connectors is neck-crick-inducing, so I'll have to pull mine out at some point.
Simply updating the firmware is very easy as long as you connect the backplane to an LSI HBA (RAID cards don't work). It's exposed as its own device in Linux under
/dev/bsg/ (and presumably in Windows), and Supermicro has an Xflash utility that does the flashing -- which has options to use either the 'in-band' connection or a COM port to talk to the expander
. Always get firmware/MFG updates directly from Supermicro.
On Areca RAID cards with LSI expanders, they provide a separate RJ45 port on the back and a DB9-to-RJ45 cable that lets you access the expander CLI, upgrade firmware, etc. My interest in accessing the UART is diagnostics and management, since my RAID card appears to hide the backplane expander too.
