@gounthar, notice the "v" character missing in your output, so it means that that particular image does not detect vector extension.
isa : rv64imafdc
For MangoPI MQ(PRO) - The thing is that there were several builds that successfully detected RVV extemsion ( RVV v0.7 ) present on c906 CPU, and there were builds that do not. I`m wandering what has changed in those images, that prevents "v" appearing in "isa" line of /proc/cpuinfo? And how to enable it again?