Paul is correct that this is a solution I have offered in the past for those having difficulty with updating. This is because some USB Drives do not "power up" fast enough to be read in time during the X32 boot process. If you use the workaround Paul described, the USB drive remains powered up since the console is only doing a "soft reset" (power to the USB drive remains on). This often works.
Regarding a list of recommended drives:
It is difficult to recommend specific brands as specifications are ever-changing and a particular brand/model from a few months ago may be manufactured differently then the current version, without any indication. I will say that I personally have had better luck with smaller size USB drives. In addition, remember to be sure that the drive is formatted to the FAT32 file system (shown as FAT in Mac OSX Disk Utility). It also can help to have the firmware file be the only file on the drive.
I have also successfully updated using a 500 GB USB Hard Dive with a lot of other data on it that had its own power supply, so I would recommend trying this if one is available to you. Hope it helps!