During an implementation of ESXi 4.1 at a customer site I experienced random crashes of ESXi during normal operations. VMware support has been investigating this issue and a probem has been found in the Broadcom’s bnx2x Inbox driver version 1.54.1.v41.1-1vmw. This issue can lead to a complete crash of the ESX/ESXi 4.1 host.
VMware has currently released a workaround for this bug and is working to provide a full solution to the issue. Information on this problem can be found in KB1029368.