@Douglas-Kryder and @Gabriel-Gabor. Thanks for your replies.
Gabriel, your post shows that it is possible, which gives me hope. This week I have followed the link that you posted, but with no success. I have executed the procedure many times, with different Omega2 units. It is strange that I seem to have enough memory left after the crash.
This is how it looks like after I have get the stack dump after typing 'pip3 install requests':
...
[ 530.773422] [ 1842] 0 1842 297 11 3 0 0 0 ntpd
[ 530.782072] [ 3146] 0 3146 9903 7633 13 0 0 0 pip3
[ 530.790729] Out of memory: Kill process 3146 (pip3) score 488 or sacrifice child
[ 530.798257] Killed process 3146 (pip3) total-vm:39612kB, anon-rss:30524kB, file-rss:8kB
Killed
root@Omega-6895:/# df -h
Filesystem Size Used Available Use% Mounted on
/dev/root 5.5M 5.5M 0 100% /rom
tmpfs 29.7M 3.3M 26.3M 11% /tmp
/dev/sda1 14.0G 75.0M 13.2G 1% /overlay
overlayfs:/overlay 14.0G 75.0M 13.2G 1% /
tmpfs 512.0K 0 512.0K 0% /dev
root@Omega-6895:/#