This page lists all of the content under the firmware topic.
We have recently been adding support to the libnvme and MCTP components of Linux that allow out-of-band communication with NVMe storage devices. One of the neat applications of this is to manage device firmware - allowing a BMC to update firmware over an out-of-band (OOB) channel, without any intervention from the host system.
The protocol for the firmware updates is specified by the NVM Express standard, so device support is generally pretty good. As long as the device supports NVMe-MI, out-of-band firmware update should work.