I've found an easy way for Apple users to update the iFly 740 (and maybe the others) using the iFlyUpdatePackage.zip method to download new weather and TFR data.
Sandisk sells a double-ended gizmo called iXpand Flash Drive that has both a USB 3.0 plug and a Lightning connector that plugs into an iPhone or iPad.
It allows you to download the iFlyUpdatePackage.zip to an iPhone, save it to the iXpand Flash Drive, and from there load it into the 740.
You can do this anywhere you have a cell signal or a wifi connection to the internet. So you can do it just before takeoff at an airport or even out in the bush. (I've done it while floating on a river in my Searey.)
The one caveat is that I've done this successfully only with a 32 GB iXpand. My 740 won't read a 128 GB iXpand. I haven't tried the other versions of the iXpand. Nor have I tried any of the competing brands of Lightning+USB flash drives.
I paid about 30 bucks for the 32 GB iXpand at an OfficeMax store, but you can probably get one cheaper online.
(I imagine that this method will work on an Android phone, but haven't tried it. Also, it should work for bigger upgrades--charts, etc.--although I haven't tried that yet.)