For those having problems, try knocking the update back of the Program box back to the v1.1 (I think). Don't use the latest version. Seem to have some issues with that, but updates worked fine on the other version.
I'll check what version numbers I'm running on what tonight, and post back up on here.

Well, the issue now is when I turn the power on from the esc, nothing happens so it won't allow me to bind to the radio. The only way to turn it off is to unplug it from the battery. When I plug in the program box it just says connecting esc and again nothing happens

Exactly what is going on with me. The programmer just cant connect to the ESC. This makes it so you cant change any settings via the programming box or the USB Link software. It also makes it so that you cant update the firmware on the ESC.

I develop hardware and software for embedded systems for a living and this is basically what happens when the device is "bricked". It happens when a poorly written bootloader or update mechanism is implemented that allows a failed update to cause an unresponsive state. This is very preventable via well written firmware. Reloading the firmware for the ESC via JTAG would surely bring the ESC back to life.

It makes me a little sad when this stuff happens because I know it is preventable.

I was able to update my V3.1 stock spec with no problem last night.

I actually had problems with the 3.43 communicating with the programmer. Bad news is it wipes out 3.42 in the process.
Is there a place to get a fresh copy of 3.42?

On my pc, 3.42 was left in the program folder, only the desk top shortcut was deleted. I removed it(3.42) manually through the control panel.

just did some testing of my own and the esc programmed just fine with no issues at all
Im in the process of doing a video and will post online .

I did find a copy on line. 3.43 actually seemed to corrupt 3.42 and it would not communicate either. I went to another computer that had 3.42 and no problems. I removed all versions of 3.* and installed a fresh copy of 3.42 that I found online. All appears to be good right now, I just won't update to 3.43 in the near future.

just completed some testing on 4 different versions on the usb link software on the same pc nothing deleted i found no issues when updating software esc and programmer 3.43 works fine .

Angelo, thanks for testing. I am sure that 99% of the time, everything goes fine. Have you ever had a failed ESC firmware update? If so, what happened?

The problem is that when the update fails for whatever reason, the ESC is left in an unresponsive state. In my case, when the update failed, nothing out of the ordinary happened. No power glitches, no computer problems, no connection problems. I had just exported the settings from my ESC to the computer so everything was working perfectly. After exporting settings, I attempted to update the ESC firmware and it failed for some unknown reason. This sounds like the case for some of the the other members here as well.

Even after this gets resolved (still waiting on my RMA request) I am going to be a little worried about updating firmware in the future unless Hobbywing acknowledges that there was a problem and they fixed it.

Im sure many of you know me very well that i will not stop unless i fix the issue even if its only 1% as that is to much for me .We have built the worlds best tech support network and i wont rest until we solve that small glitch.Rest assured im on to it .Its 1 am and im still going lol.

I have just had the same happen to me, I just received my XERUN-120A V3.1 today and had a test in the garden all working fine, I then decided to see if there was an update and there was so did the v140627 using the USB Link V3.43. now it wont work or connect to anything, and was really hopeing to use my new kit for Sunday

What happened was I ran the update to 3.43. It would not communicate with the programmer or esc. I then tried to use 3.42 and it would not communicate either. I removed 3.43 hoping that would fix 3.42 but it did not. I used another computer with 3.42 and everything is fine there. My next test is to go back to the first computer where I removed all versions of 3 series software and installed 3.42 from a jump drive. I wont get to test that until later today. Just for info the computer having the problem is a XP machine.

So, saying it works fine doesn't address the issues people or I are having. Since it works fine for you all is good. I'll try to find someone that can help...

that's not what he is saying. What he is saying is he hasn't been able to replicate the problem but he is working on it and will work on it until he fixes it.

I have updated 3 HW v3.1 to the latest version, 3.43, with no issues. I removed all other HW software installed 3.43 and updated, win7