You might want to try changes these settings and do a host reboot.
VMware support had us try this first - and these settings have been applied throughout all of our testing.
( So it might be in addition to the firmware levels, you also need to apply these settings. )
esxcfg-advcfg -s 40000 /LSOM/diskIoTimeout
esxcfg-advcfg -s 5 /LSOM/diskIoRetryFactor