Nexstar hand controller firmware update failed, display showing odd squares

Barry Ziober · Dec 5, 2025, 06:30 PM

trying to update firmware on nexstar hand controller, every time i try it says update unsuccessful, tried resetting and but didn’t work, then tried use newest cfm but that didnt work, contact celestron support but they are having holiday party today and closed down early, any suggestions how to update, now my controller has just a bunch odd squares on display. has anyone else seen this and got passed it? thanks much

Have you tried pressing the number 4 and the Celestron logo button at the same time when resetting the hand controller?

Barry Ziober · Dec 5, 2025 at 07:28 PM

celestron told me to hit 0 when turning on mount, i will try 4

🤞good luck!

Barry Ziober · Dec 5, 2025, 07:37 PM

thanks but no luck, frustrating

Ok, yes, that’s absolutely frustrating. I think the hand controller is bricked, but you may be able to force bootloader mode on the HC and see if you can “reflash” it. I’m assuming this HC is one with a USB port at the bottom of the wand and not a RJ45 jack, right?

Barry Ziober · Dec 5, 2025, 08:13 PM

yes usb at bottom

Alright, this may take a while and, of course, not work—however; you may be able to recover the HC and force it to reflash the HC in bootloader mode. Try these steps:

Step 1 Disconnect Everything:

• Power off the mount and disconnect the USB cable from the HC.

  Step 2 Access Bootloader:

• Reconnect the HC into the Mount ONLY

• Hold down the Celestron Icon Button and the number 7 button

• Keep holding down those buttons and turn on the mount (note you are ONLY connected to the mount at this time)

  The HC should start flashing and say something like “BOOTLOADER” or “BOOTLOADER MODE”

  Step 3 Connect HC to Laptop:

• Reconnect the HC via usb cable to the laptop/PC.

• Launch Celestron Firmware Manager

  Step 4 Click “Seek Devices” and “Update”

• As noted in the step, see if you can select the “Seek Devices” button and the “Update” button.

• Let it rip.

  These steps may not work, but it’s worth a try. If it doesn’t then you’ll probably have to get another hand controller.

Barry Ziober · Dec 5, 2025, 08:50 PM

thanks much for trying, my problem is i never see this “The HC should start flashing and say something like “BOOTLOADER” or “BOOTLOADER MODE”” but just a bunch of weird squares

Well, that’s a bummer. I’m out of ideas for trying to revive the HC, might need to just order a new one.

Rick Veregin · Dec 6, 2025 at 02:09 AM

I’ve seen those deadly squares in the past too. It has been a long while since I did this, I will never try a Celestron update again unless things are totally failing. I still have that mount, but don’t use if very much anymore.

I wish I had taken good notes, or any notes that I could find now. I do have the general instructions though. And my recollection may be off, but here is what I recall.

• Change to a really short top notch USB cable—this I know was when I was at my wits end and it finally worked.

• Delete the CFM you had.

• Disconnect the HC from the mount.

• Connect the HC directly to your computer using the USB cable.

• Launch the Celestron Firmware Manager (CFM)

• Seek Devices in CFM, it will find the HC and show a "BOOT LOADER" message.

• The Celestron Logo and 4 may help, but I don’t recall when to do this.

• Start the Update and DO NOT disconnect the cable or power off anything until CFM reports success.

• Verify by disconnecting and reconnecting the HC to the mount, then check the firmware version in the HC menu.

• If the BOOT LOADER doesn’t show up, ignore it, and try pressing the update button anyway.

Some of the above worked, some maybe were things I tried but did not work. I can tell you I got it eventually, not sure how many times I tried, trial and mostly error, but I definitely tried the same and different things over and over to get it.

Good luck

Rick

I haven’t seen this method work before, but if it does that would be awesome!