I released v1.0 of the port of OpenBMC to ADLINK Ampere Altra systems yesterday.
The release along with upgrade instructions can be found at https://github.com/bcran/openbmc/releases/tag/v1.0-bexcran
Unfortunately I haven't been able to find a path to switch from MegaRAC to OpenBMC. So if anyone would like to run OpenBMC instead of the MegaRAC firmware that comes with the systems, please contact me and I can send you replacement SPI-NOR EEPROMs.