If you own an Nvidia Shield Pro box you may have a bad hard drive. Nvidia announced this weekend that a small number of Shield Pro boxes are experiencing problems and may have defective hard drives. If you own one of these units Nvidia is offering a free replacement.
If your Nividia Shield Pro box shows the fasboot screen after you updated to 1.4 you should get it replaced; even if you think your Shield Pro is working perfectly.
Also, if you see severe or persistent pixilation in the tiles at the top of the Android TV home screen you should get your Shield Pro box replaced.
If you have any of these issues you can contact Nividia via live chat on their site here: http://nvidia.custhelp.com/app/chat/chat_launch
If you are an Nvidia Shield Pro box owner whose unit does not have any of these issues, I would not worry about your device; it is not part of this recall.
It is impressive to see Nvidia respond so aggressively to an issue that is affecting a small number of devices. Often recalls such as this only happen after a large number of complaints, and long after many affected users have paid to replace or repair devices out of their own pocket. So, be reassured that Nvidia is taking the Shield Pro box problem seriously and seems dedicated to making sure you have a great experience with their device.