Please see FINAL UPDATE at bottom -- no solution yet....
I have an Odroid-C2 (aarch64/armv8-a) I've been playing around with for a couple of weeks in my spare time. For remote GUI applications xpra-winswitch is working fine. I can even start xfce4 and remote the desktop using xpra, which is nice.
I've been trying x2go as well and it doesn't work on the Odroid-C2. Every time I try to connect /usr/lib/nx/bin/nxagent core dumps. x2go works fine on my RPi3 (armv7h).
I did the most obvious thing (at least to me) and tried to build the nx packages with debugging turned on. I used `options=('!strip')' and `export CFLAGS="-march=armv8-a -O1 -g -pipe -fvar-tracking-assignments"', `export CXXFLAGS="-march=armv8-a -O1 -g -pipe -fvar-tracking-assignments"' in PKGBUILD for nx, then built with makepkg and reinstalled libxcomp, nx-x11, nx-xcompext, nxagent, x2go-agent. I then installed gdb and ran `coredumpctl gdb' hoping to find where it crashed but what I got is not helpful:
$this->bbcode_second_pass_code('', '$ coredumpctl -1
TIME PID UID GID SIG PRESENT EXE
Tue 2016-05-24 20:51:48 UTC 21661 1000 1000 11 * /usr/lib/nx/bin/nxagent
$ sudo coredumpctl gdb
PID: 21661 (x2goagent)
UID: 1000 (alarm)
GID: 1000 (alarm)
Signal: 11 (SEGV)
Timestamp: Tue 2016-05-24 20:51:48 UTC (22h ago)
Command Line: /usr/lib/nx/../x2go/bin/x2goagent -extension XFIXES -extension GLX -nolisten tcp -nolisten tcp -dpi 75 -D -auth /home/alarm/.Xauthority -name X2GO-alarm-56-1464123097_stDXFCE_dp24 :56
Executable: /usr/lib/nx/bin/nxagent
Control Group: /user.slice/user-1000.slice/session-c72.scope
Unit: session-c72.scope
Slice: user-1000.slice
Session: c72
Owner UID: 1000 (alarm)
Boot ID: 71c5fa174dcd44d8904cb11430c96791
Machine ID: aa43b3b1b4f54e06a0b23ebd20611a4e
Hostname: alarm
Coredump: /var/lib/systemd/coredump/core.x2goagent.1000.71c5fa174dcd44d8904cb11430c96791.21661.1464123108000000000000.lz4
Message: Process 21661 (x2goagent) of user 1000 dumped core.
Stack trace of thread 21661:
#0 0x003042415a74614c n/a (n/a)
.
.
.
warning: core file may not match specified executable file.
[New LWP 21661]
warning: Could not load shared library symbols for linux-vdso.so.1.
Do you need "set solib-search-path" or "set sysroot"?
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/usr/lib/libthread_db.so.1".
Core was generated by `/usr/lib/nx/../x2go/bin/x2goagent -extension XFIXES -extension GLX -nolisten tc'.
Program terminated with signal SIGSEGV, Segmentation fault.
#0 0x003042415a74614c in ?? ()
(gdb) where
#0 0x003042415a74614c in ?? ()
#1 0x323042415a74614c in ?? ()
Backtrace stopped: previous frame identical to this frame (corrupt stack?)')
Since /usr/lib/x2go/bin/x2goagent is a symlink to /usr/lib/nx/bin/nxagent and /usr/bin/x2goagent and /usr/bin/nxagent are shell scripts I guess gdb isn't going to work like this???
I don't have experience with this code so I'm not sure how to provide helpful info. HTH.
UPDATE: I uncompressed the lz4-compressed coredump and ran:
$this->bbcode_second_pass_code('', '$ sudo gdb /usr/lib/nx/bin/nxagent /tmp/core.x2goagent')
directly but got the same result as above. TIA.
FINAL UPDATE: I've tried messing with x2goclient settings to connect to the Odroid-C2 running x2goserver. I messed with Session preferences -> Input/Output -> Keyboard in the GUI. When set to "Auto-detect keyboard settings" the server side on the Odroid-C2 dumps core
When set to "Do not configure keyboard" or "Configure keyboard -- pc105/us" (no variant setting) it fails to connect. In these latter two cases, the server side gives an error message, "keyboard file not created: Is a directory", which seems to be infamous in that it doesn't point to an obvious solution. Wish I could be of more help at this point.Clemmitt