Of course it works, I think rainisto meant his advice for people using windows hosts.

Another way to do the transfer, is to boot the device with a rescue kernel (or rescue mode in ubiboot if you use that) and then just copy the file to the exported partition.

I wonder though where the original poster would want to upload that large file to, if the MyDocs is formatted as FAT... As far as I know that's the only partition sized large enough to hold anything like that.
(unless there's been some partition resizing going on...)