@Neo_Reloaded
Yes it was a migration from 6.0.2 to 6.1 + login to DSM, sudo -su as root user, execute "cp lib/modules/update/* lib/modules/"
Thanks for your time and answer
I've successfully updated Gen8 baremetal DS3615xs to 6.1.1-15101 Update 2 using 1.02 alpha loader. All seems to be OK except a HIGH security warning about DSM system files have incorrect hash values (when running Security Advisor).
I know it's not a big deal but still ... is this normal ? Many thanks for your work and time.