Yes, if you have 2 SD cards, you can mirror both and install hypervisor. Is this UCSM integrated or standalone (CIMC)? M4 servers have special SD card controller (FX3S) which have auto-sync feature that can resynchronize the cards automatically without user interaction.
More can be found here: https://www.cisco.com/c/en/us/products/collateral/servers-unified-computing/ucs-c-series-rack-servers/whitepaper-c11-734876.pdf
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