Just ran into a Cisco UCS bug. When upgrading the UCS firmware of your environment, some B200M4 blades may reboot spontaniously. I won’t tell you how I found out, but be sure to read this article:
Cisco Bug: CSCut61527 – B200M4 could reboot on shallow_chkpt when BMC returns invalid FRU data. https://tools.cisco.com/quickview/bug/CSCut61527
Affected firmware: 2.2(3) and 2.2(3a)A according to the KB. My upgrade was from 2.2(3c) to 2.2(3f).
According to the KB this issue should be resolved in 2.2(3g)A.