Cannot Change vSwitch0 MTU to 1522 in ESXi 5.5 - Dell R300

Hello Dell Community

I have a Dell R300 with ESXi 5.5, and their  vSwitch0 in 802.1q trunk with a C2960 switch. I tried to change the vSwitch0 MTU from 1500  to 1522, however, the ESXi gave the following error:

Fault Details:
	Status: An error occurred during host configuration.
Error Stack:
	Operation failed, diagnostics report: Unable to set MTU to 1522 the following uplinks refused the MTU setting: vmnic1
Additional Fault Details:
	VC Build: 1312298 Error Type: PlatformConfigFault Entity: HostNetworkSystem Method: UpdateVirtualSwitch

I updated the driver acording to vmware guidelines, however the issue persists. Here is the updated esxi driver version:

~ # ethtool -i vmnic0

driver: tg3
version: 3.137l.v55.1
firmware-version: 5722-v3.11, ASFIPMI v6.03
bus-info: 0000:01:00.0

Could be necessary to update also the NIC firmware ??

Regards.