If you connect to your board using MavProxy, a telemetry log with automatically be saved into the file mav.tlog.
Entirely true, but the question was on dataflash logs 
So something like sudo mavproxy.py --master=/dev/path/to/pixhawk/from/odroid
Pleae avoid running mavproxy as root. If you are receiving permission
errors opening the serial devices the typical solution is to add your user
to the “dialout” group. Using “sudo” is a really, really big hammer and
can cause issues down the line - usability and security issues. Once you
have run it once as root you will typically need to remove several files
that are now owned by root - for example, the mav.tlog and mav.tlog.raw
files you’ve mentioned. Trying to subsequently run MAVProxy as a normal
user will give you permission errors opening those files.
Downloading dataflash logs using mavproxy is accomplished using the
“log” module. Something like:
module load log
log list
log download 3
log download all
log erase