P410i controller - vmware esxi lost connectivity

Hello, I have an HP Proliant ML350 G6 with P410i controller. It's running VMware ESXi 5.5 U2. I'm having performance issues and I see an error many times a day in the esxi logs. I found some other similar discussions and it seems that I need to upgrade the driver and/or firmware to resolve the issue.

ERROR: Lost access to volume 5351d599-a5f47404-1c5c-1cc1dee8140a due to connectivity issues. Recovery attempt is in progress and outcome will be reported shortly.

Controller details:
Controller Status: OK
Hardware Revision: C
Firmware Version: 5.14
Cache Board Present: True
Cache Status: OK
Cache Ratio: 50% Read / 50% Write
Drive Write Cache: Enabled
Total Cache Size: 1024 MB
Total Cache Memory Available: 912 MB

ESXi Driver Details:
~ # cat /proc/driver/hpsa/hpsa0 | grep Driver
Driver Version: HP HPSA Driver (v 5.5.0.84-1OEM)
Driver Build: 01

This is the only server running the company's critical apps, so I need to be extra careful during this upgrade. To that end, my questions are:

1. I see firmware version 6.64 (B) is available and assume that is the best one to use?
http://h20566.www2.hpe.com/hpsc/swd/public/detail?sp4ts.oid=3884318&swItemId=MTX_a8f0765b51594bf584992ddbe1&swEnvOid=4166
 
2. I see the firmware has several update methods, and for me I think the direct upgrade from the tech support console is the best way to go. Is this method reliable?

3. Should I upgrade the firmware first, then the driver? Or update the driver first?

4. The HP site lists this driver version as the latest. Is this the best one to use for this issue?
5.5.0.106-1OEM.550.0.0.1331820.x86_64.vib
http://h20564.www2.hpe.com/hpsc/swd/public/detail?swItemId=MTX_51c7978b3b5244fbb807764527