Looking for Sandisk SSD firmware for my X41T

[Tasurinchi]

Some weeks ago I bought a ZIF SSD for my X41T in eBay from this seller. It's a 32GB Sandisk, model number SDU5B.

So far it's working fast and silent and no isues have appeared, however, I first installed Win7 Ultimate and did a benchmark using CrystalDiskMark. The performance results were far lower than the table from this topic. At that time I did not care that much, as I did not had all drivers for the X41T installed and soon after I switched to Linux Mint.

Now I've found out that I have a very old firmware and was trying to get the newest one, but according to this link Sandisk it's not providing support or upgrade utilities. Neither the Ebay seller will provide a firmware.

Does someone here know where to get this firmware? Or did someone upgrade the firmware before and have the file stored somewhere? I could not find a source in internet

Thanks a lot in advance for the help!

Regards