The setup outlined here is based on the information and code shared by the original author (Glen) at the following link/blog.
DISCLAIMER: Use it at your own risk. I am not responsible for any loss or damage to your property.
0. Use the Transcend tools (andriod app or ios app) to configure your card to connect to your home wifi network; while you are at it, change admin user, cards wifi ssid, passwd etc. Make sure your card successfully connects to your wireless network and note the IP address assigned to it by your home wifi router.
1. Download and extract http://selvans.net/public/custom.tar.gz in your desktop computer and edit the autorun.sh file to uncomment the line below for telnet access, i.e. remove ‘#’
telnetd -l /bin/bash &
2. Edit the access.sh file and change “trusted_network” variable to match yours
3. Insert your SD card in your computer and copy the entire custom/ directory from step #1 above to the root directory of SD card. In addition, also copy autorun.sh to root directory of SD card.
4. Remove card and reinsert it into your computer.
5. Now you should be able to telnet to your card from your linux box, i.e. telnet
In the examples shown below 192.168.xxx.xxx is my WifiSD card and 192.168.yyy.yyy is my ubuntu desktop
arul@cheetah:~$ telnet 192.168.xxx.xxx
Connected to 192.168.xxx.xxx.
Escape character is ‘^]’.
bin home lost+found sbin usr
config_value init mnt sys var
dev lib proc tmp www
etc linuxrc root ts_version.inc
6. Once you are logged in via telnet as shown at #5 above, you need to create dropbear hostkeys and copy them to your desktop to include in /custom directory on SDcard. Note: I have included two dummy files in /custom directory you need to replace them by creating your own key files. i.e. follow the example below but use your IP address and your user name of course.
# dropbearkey -t rsa -f /tmp/dropbear_rsa_host_key
# dropbearkey -t dss -f /tmp/dropbear_dss_host_key
# scp /tmp/dropbear_* email@example.com:/tmp/.
Now, copy the 2 files from your /tmp directory to the custom/ directory on the SD card by replacing them.
7. Create (or copy if you already have a dsa public key) in your desktop to the /custom directory as authorized_keys. Note: I have a dummy authorized_keys file that you need to replace.
ssh-keygen -t dsa
cp ~/.ssh/id_dsa.pub custom/authorized_keys
8. Once you update all the key files in custom/ directory in the card, unplug your card and plug it back into your device (computer or camera) one last time. Once the card boots, you should be able to ssh into your card or scp files, or setup automated scripts to copy files from card to your desktop… and pretty much do everything you can do with ssh!
arul@cheetah:/tmp$ ssh firstname.lastname@example.org
# cat /proc/cpuinfo
Processor : ARM926EJ-S rev 5 (v5l)
BogoMIPS : 421.06
Features : swp half fastmult edsp java
CPU implementer : 0x41
CPU architecture: 5TEJ
CPU variant : 0x0
CPU part : 0x926
CPU revision : 5
Hardware : KeyASIC Ka2000 EVM
Revision : 0000
Serial : 0000000000000000
Sat May 3 16:13:53 UTC 2014
# /sbin/busybox-armv5l uname -a
Linux (none) 18.104.22.168 #137 PREEMPT Fri Mar 22 18:21:52 CST 2013 armv5tejl GNU/Linux
Connection to 192.168.xxx.xxx closed.
arul@cheetah:/tmp$ scp -r email@example.com:/mnt/sd/DCIM/* .
DSCN0254.JPG 100% 836KB 278.8KB/s 00:03
Have fun with ssh/scp on your Transend WifiSD card!
This is where I got the prebuilt busybox and dropbear binaries for reference. They are already in the custom/ directory for convenience.
arm5l busybox: http://busybox.net/downloads/binaries/latest/
arm5l dropbear: http://landley.net/aboriginal/about.html