Copying files from PC to "external" SD card I've got AirDroid and SSHDroid installed on a ZTE Axon 7 running 7.1.1. The phone has a micro SD card in it, and it can access (read from) that card successfully. What I can't do is copy files onto it. I can log in via ssh and see the file system, but I can't touch it.

I've had a Moto X Pure for the past year, and via SSHDroid and AirDroid I can readily copy files to the SD card.

Is this just a "security" (ie, "pay somebody") thing in the more-proprietary OS on the ZTE phone?

Obviously I can mount the micro SD card directly on the computer, but juggling those tiny cards is kind-of a pain. If there are other solutions, I'd be grateful.

edit &mdash; I've tried MTP with the Axon. I plug in the phone and tell it I want to connect as a "media device" with MTP. I then run mtpfs (I'm running Linux on the laptop; Ubuntu 16.04) and I get:

Listing raw device(s)
Device 0 (VID=19d2 and PID=0306) is a ZTE V790/Blade 3.
   Found 1 device(s):
   ZTE: V790/Blade 3 (19d2:0306) @ bus 2, dev 98
Attempting to connect device
Android device detected, assigning default bug flags


Then it just sits there. (I've never had much luck with MTP.)

edit again &mdash; ADB seems to work. I don't move files that much (mostly music and audiobooks) and while ADB is a pain it's easier than fiddling with the cards.
If you're not insisting on a wireless transfer, using an USB cable would give you at least two options:


Using mtp
Using adb


With MTP, on connecting the device to your computer you should usually get the option to open it in some file explorer (does so on Windows and on Linux at least). For ADB, you could use adb push to push files to your SD card – or, for your convenience, use an ADB GUI (some are listed here at my site.

For the latter, once connected via USB cable you could make it switch to TCP mode if you need it wireless. Without root, this must be repeated after each boot – with root, there are ways to initiate it without a cable.

Details can be found e.g. via the corresponding tag-wikis: adb and mtp.

Disclosure: The first two links lead to my Android website.