Hi Ivan,
How much memory does the server have available? If the limit is increased, but there's not actually that much memory available, you might still get this message. If your server config allows it, and you have enough memory allocated to the server, then you might try increasing the limit to 1024MB - once the installation is complete, you should be able to scale this back a bit if needed.
One more thing - once you've made changes to any of the php.ini files, you might want to restart your services, such as PHP-FPM - and any other caching engines, such as memcached. I would also suggest clearing the application cache. I don't know what all of these commands will be on Debian, but I've included Ubuntu examples, as well as other information that might be of use to you, in this previous thread:
Follow the links there and try those suggestions to make sure you are editing the right files, etc. Let us know if that helps!
Regards,