I upgraded to 4.10 and now (at least I'm pretty sure this only started post-upgrade) I can no longer mount the 820 as a folder. I.e., I plug in a USB cable and nothing happens, other than the 820 saying it's charging. I try turning the 820 off and on, try doing this when it's plugged in or disconnected from USB, try holding power down for 15s or so to make it really switch off, try different USB cables, different USB ports on my laptop, and two different computers.
I'm planning to send my 820 back. It has many other problems, which I can (unhappily) live with. But not being able to load new courses onto it is something I definitely can't live with.
Does anyone at Garmin actually ride a bike and use these products before they're launched on an unsuspecting (or naively optimistic) public? A public already suffering from the previous generation of deeply flawed and expensive Garmin bike computers :-( :-( What a terrible strategy - piss off the people who could be your core supporters. I hope competition will increase in this market. I'd love to have a decent alternative to Garmin. I feel deceived and ripped off.