According to the Firmware Upgrade Manual you should be able to check the firmware version of the drive in Device Manager. Presumably the device name will reflect the firmware version.
If not try going to the
Details tab for the device in Device Manager and select
Hardware Ids in the
Properties dropdown you may see an extra bit of information in the drive name which may show what the firmware version.
As a rather amusing aside, I can see why your firmware update is failing, as on their download page:
*CURRENT FIRMWARE RELEASE is v1.7
Note: Current FW must be v1.6 before flashing to v1.7
Please backup all data on the SSD as a precaution
I cannot immediately see V1.6, so it's rather stupid that they do not post previous versions of the firmware if it requires an incremental update.
Are you sure you don't have a Vertex 2 or Vertex LE whose firmware is at V1.35?