Jim S88

I was having the same issue. My MZ-24 was stuck on 1.032 firmware just refused to go further with same error in above thread. Tried countless times. I emailed Graupner Germany to enquire about the pro upgrade but I have not heard back yet BUT.......... I took the back off to fix a broken bit and found a CR2032 lithium battery, my tx is about 10 years old so guessing it was about time to change it. Swapped it out for a new one and put it all back together. Ran the upgrade using grStudio version 4.9.3.2 and it took a lot longer to download the firmware file, around 60-90 seconds. Then rebooted and bingo, version 1.056 all good to go. Can't guarantee this will work for all but worth a try. There are 6 Philips head screws on back (2 under foam side holds which replace back easily) plus you need to remove the two hex bolts on top, either side of antenna. Take care removing/replacing back and side potentiometers are bit fragile and have to ease through slot in back. Good luck 🙂