https://uk.yamaha.com/files/download/other_assets/8/805548/en201604montage.pdf

Hello Lenwood - Jason has provided the official list, but if you look at the bottom you'll see Yamaha wash their hands of any guarantee that they'll work! Basically, it MUST be a USB2.0 (NOT 3.0), and be free of ANY partitioning or pre-programming if you use it for updates. As they're so cheap anyway, I keep an old 2Gb just for updates. and a 16Gb for a back-up. Neither is on Yamaha's list, by chance. Can't do any damage should it be incompatible - it just won't work!

The disclaimer from Yamaha is necessary because although Yamaha can qualify some flash drives of a certain manufacturer and part number works with Montage - the ones they have "in hand" for testing - there's no telling how the manufacturer of this flash drive may change the internal components over the course of a flash drive production run. Also, there may be alternate parts (internal) which those variants were not tested. Furthermore, these memory types have a few parts to them - the memory fabric and the memory controller. The memory controller will often rev with firmware updates even if the part number for the memory chip itself (which internally has the memory fabric+controller) does not change. ... not to mention counterfeit products out there that are sold as a popular manufacturer's part - but is not - and often does not even have the advertised size as the part number represented.

So there are real limitations in how wide one can cast a net when it comes to testing USB flash drives.

It's still a reasonable list to use for the less adventurous. Since no (Montage) firmware update or user data backup is going to exceed 4GB - I would still recommend a 4GB or below drive as placing too much data on these drives is a liability concern (in my opinion) and flash drives should be used for data transfer - not data storage. Just a go-between like SDCards in cameras are. Note: this is just my preference/opinion. There's nothing wrong with using larger drives if you have other priorities pulling for the greater storage capacity. One reason to use a larger device is to depend on "wear leveling" - and only use a fraction of the capacity at any given time. Assuming the controller is well behaved (doesn't have bugs) - using a large drive will extend the life of the data as the unused space will have its turn hosting your data if the used space starts to "wear out" - primarily from writes.

hi i use many usb flash disk i have now a 3.0 64 usb drive and also work perfect i have more and try them all the all work perfeckt

Hello Rob - that's interesting! I thought USB3.0 would be better for driving the external monitor I have on the Montage, but the one I had didn't work at all. Zilch - not even a green screen. But the USB2.0 did work! Might have been the external video card though, which is supposed to support both. I now use a powered USB2.0 4 port hub, which enables both the back-up USB and the external card to be plugged in, which works just fine, with a VGA 2-way switch to change from Montage to computer and back again at will.

Hello Jason - I see that many of the USBs listed by Yamaha are 32Gb, although as you say, with Montage's somewhat limited architecture of not allowing the USB to be directly accessed as a Bank (like in the Tyros) there does't seem much point ... maybe one day ... ?