Tried updating libcrypto++9_5.6.1-6_armhf.deb
Updating the lib on your system won't do anything. As I mentioned previously, the CryptoPP source is copied as is in the armory repo, and statically linked to boot. It literally ignores what your system is carrying. You would need to pull the source from CryptoPP's repo, copy it over that source in the Armory repo (/cppForSwig/cryptopp) and build that to effectively update the lib.
This may not be relevant however, since your discovery suggests the issue has more to do with Qt4's interaction with the X server (or PyQt4 for that matter).
Ok, I misunderstood thinking that being related to bus error.
I have spared some time installing ubuntu 14.04 on my Galaxy S4 through LinuxDeploy replacing 18.04 on which I could handle tx signing flawlessly.
Then came with all the needed dependencies and armory 0.96.5 compiled exactly by my original phone(Forgot to mention, it is a Samsung I717 aka. Galaxy Note AT&T variant).
Bus error show up again when signing certain transactions.
So at least I can conclude that the bus error issue has something to do with ubuntu14.04(armhf) installed by LinuxDeploy.
Anyway,it's quite a relief that I could still use a cellphone as offline signing device for armory.