See here on how to debug the illegal instruction problem: https://forums.urbackup.org/t/ubuntu-glibc-not-installed-or-too-old/
i.e.
wget “https://hndl.urbackup.org/Client/2.4.9/UrBackup%20Client%20Linux%202.4.9-dbg.sh”
sh '“UrBackup Client Linux 2.4.9-dbg.sh” --target /tmp/urbackup_installer --noexec
tar xf /tmp/urbackup_installer/install-data.tar.gz -C /tmp/urbackup_installer/
gdb --args /tmp/urbackup_installer/i686-linux-android/urbackupclientbackend --version
run
bt
x/i $pc
Also please post the output of cat /proc/cpuinfo.
Thanks!