No. Unless you are experiencing a specific, verified firmware bug and have the exact file from the manufacturer’s support engineer, do not attempt it. The risk of bricking a functional (if modest) digital piano far outweighs any possible gain. If you want new features, buy a newer keyboard. If you want stability, keep your SF-720 exactly as it left the factory.
This is a specific technical request, so a "deep review" requires moving past generalities and into the operational reality of the (a digital piano/workstation) and the process of downloading/installing its software updates. solid sf-720 software update download