Sorry, this is more a request for information than a real issue.
I was wondering if this modded firmware preserves the Crypto HW accelerations and allow the installation of OpenVPN ?
Yes it keeps the hw acceleration, if it even has that. It doesn't directly enable installation of software packages, but you probably can drop a binary somewhere when you SSH into the router.
Sorry, this is more a request for information than a real issue. I was wondering if this modded firmware preserves the Crypto HW accelerations and allow the installation of OpenVPN ?