Sorry, I should have been clearer, I was only addressing the specific situation here. There are many exceptions, HP often only provide a way to update the BIOS in Windows. Most motherboard manufacturers however do provide several methods, usually one through an application in Windows and one accessed from the BIOS or a key pressed during the POST sequence, and in this case I would always recommend to update it using the former method rather than the latter. If they provide a method to create a bootable disk, that's usually fine too. We exclusively run HP machines at work and they're a mixture in terms of BIOS updates - most can only be updated from within Windows, some let you create a bootable disk, and one or two have a section in the BIOS to load an update file from a disk.
I'm not saying updating from within Windows is guaranteed to go wrong, just that it's an additional risk which I would advise anyone to avoid where possible. I've only had a few BIOS updates go wrong, out of probably thousands. Some were because we had a power issue as I was performing a flash on several machines but they all recovered from the backup BIOS. One was on an EVGA board and was down to their bootable flash utility being complete garbage, thankfully that board has three BIOS chips so that wasn't an issue. The others have also been down to exceptional circumstances. On the other hand the number of issues I've dealt with from customers flashing their BIOS within Windows is significantly higher.
