What do you mean by "firmware for VMware"? Firmware is for hardware, so you probably mean BIOS, which you'll have to check with your server vendor.
Or maybe you mean firmware for an FC HBA or iSCSI HBA, in which case you'd have to check the VMware HCL and/or look on the HBA's vendor pages
If you can be more specific on what you're looking for, maybe we can help you better
-Michael