just letting you guys know that Firmware v. EXM04B6Q is now available. I updated my 256GB 850 pro to it and it seems to be working fine no notable issues. benchmark shows it has the same performance within a +/-1% margin of error. checking the Samsung support page for the latest firmware only lists the EXM03B6Q. Samsung magician is where I found the update.
Same thing here, Magician v4.9.7 was not offering any firmware update for 2TB 850 Pro...was just showing EXM03B6Q as the latest one. So I downloaded the new EXM04B6Q firmware from Samsung's official Tools & Software webpage and updated successfully with bootable USB following Samsung's Firmware Update Utility Installation Guide. Strange thing happened after update...now Magician offers me to update my disk's firmware to EXM03B6Q, which basically would be a downgrade. My guess is that only those who already have installed Magician v5.0.0 can see the right firmware update but I could not know for sure...I'm not willing to update Magician to the latest version as it lacks some of the features v4 has.