After spending quite a bit of time fixing an issue with my Thunderbolt, that was shutting down randomly, I finally figured out a fix without going to Apple repair. Hope this will be of help to you too!
Download the latest drivers, firmware, and software for your HP Thunderbolt Dock 120W G2.This is HP’s official website that will help automatically detect and download the correct drivers free of cost for your HP Computing and Printing products for Windows and Mac operating system. MacOS Catalina brings plenty of features and apps to get excited about, but as with all software updates, you can expect some bumps along the way. That shouldn’t come as a surprise, though, as. Click on the Software Update; Click on the Update button next to the latest OS X version in the Mac App Store. Intel-based Macs have a System Management Controller (SMC) that can be reset as a possible fix for Thunderbolt Display issues. Shut down the Mac; Plug in a MagSafe or USB-C power adapter to a power source and to your computer.
Custom reference modes require a firmware update for the Pro Display XDR. As of macOS Catalina 10.15.5. While the Thunderbolt Display had a 27-inch panel with a QHD resolution of 2560x1440.
Update your Mac to the latest version of OS X
- Click on the Apple logo in the top-left menu;
- Click on About This Mac in the drop down menu;
- Click on the Software Update;
- Click on the Update button next to the latest OS X version in the Mac App Store.
Reset SMC
Intel-based Macs have a System Management Controller (SMC) that can be reset as a possible fix for Thunderbolt Display issues.
- Shut down the Mac;
- Plug in a MagSafe or USB-C power adapter to a power source and to your computer;
- On the Mac’s built-in keyboard, press the left side Shift-Control-Option keys and the power button simultaneously;
- Release all the keys and the power button at the same time;
- Press the power button to turn on the Mac.
On Macs with MagSafe power adapters, the cable’s LED might change states or temporarily turn off when you reset the SMC.
Reset Your Mac’s NVRAM or PRAM
- Shut down the Mac;
- Turn on the Mac while pressing and holding the Command-Option-P-R keys;
- Keep holding these keys until the Mac restarts and you hear the startup sound for a second time;
Power Cycling
Shut down and disconnect both your Mac and Thunderbolt Display from AC power 30-50 seconds.
- Disconnect the Thunderbolt Display’s cable from your Mac;
- Disconnect the Thunderbolt Display from AC power;
- Disconnect all USB peripherals and any cables plugged into the Thunderbolt Display;
- Wait at least 30 seconds before powering on your Mac and Thunderbolt Display.
Thunderbolt Display Firmware Update Catalina Free
How Do I Update My Thunderbolt Display Firmware
Thunderbolt firmware update (for older OSX)
Follow this link to download the Thunderbolt Firmware update
Separate Thunderbolt cable
It is not unusual for the thunderbolt cable to get damaged over time (due to bending). Try connecting using standalone thunderbolt cable (can be purchased from Apple).