Yes, I have to concur this long awaited update (which if it were not for OK-Guy a while back informing me of impending update) has corrected the only short comings I found with this magnificent machine which in all honesty did bug me limiting me to listening to this much as I would of liked to my normal mileage I usually put on Walkman's.
It seems the mid's have been balanced out to give an even performance now across the spectrum giving a more realistic soundstage and has been executed just right but it is not a subtle correction either as they have also tweaked the bottom end and top region with the bass notes even more linear than before and can hear the different frequency's the bass can deliver whilst it travels further south before a note has finished.
The top end is even more subtle in resolution now and sounds even closer to reproducing a realistic sounding symbol sound. Vocals also seem even more prominent in a good way.
Even the noise floor is lower for me, not that it was high to start with but sounds like it is on an even blacker background now with just eerie silence between the instruments.
The update actually does bring improvements all round in the sound department as well as sorting out the shallow mids. I'm over the moon to be honest and was so taken aback by this vast improvement it kept me awake until 2.30am this morning as every song was even more transient than before on the ZX1 which now makes live performances now more dynamic and lively as they had a tendency to sound flat even with recordings that were anything but.
This is now a little reminiscent of the balanced mids of my old X series but just with ten times more resolution and more accurate and wider soundstaging (which has not been to affected from the update as far as I can hear).
Cannot believe how this update has has nailed the mids and at same time improved the bottom and top end. Big thanks to Sony team for acknowledging and rolling out this improvement as I'm now 100% hooked to putting in some serious listening hours on this over the Easter weekend.
If you do need to pair the ZX1 with a portable amp/dac at some point for bigger cans then just don't put the thoroughbred in the stable with a donkey