Migration Failled oc v6 to v8 on Synology

Please help us by providing the following info. Before posting please also check the pinned "Known issues" threads and make sure that you're running the latest available version for your oC release: https://owncloud.org/changelog/

Steps to reproduce
1.so I tried to delete owncloud v6 Synology package but it keeps saying need MySQL (MariaDB) root password
2.I've got root password working just fine in MyPHPadmin or command line MySQL statement :
mysql -u root -pPSSWORD YourDB
3.

Expected behaviour
the package should erase owncloud MySQL db schema but I got stucked with message :"Failed to uninstall package, Incorrect MySQLroot password"

Actual behaviour
it keeps stucking at step : "Failed to uninstall package, Incorrect MySQLroot password"

Server configuration
Operating system: DS Station v6
Web server:
Database: MySQL / MariaDB
PHP version:
ownCloud version (see ownCloud admin page): v6.x
Updated from an older ownCloud or fresh install: no
Special configuration (external storage, external authentication, reverse proxy, server-side-encryption):

ownCloud log (data/owncloud.log)

Please paste possible errors in the following code block, see https://central.owncloud.org/t/how-to-find-webserver-or-oc-logfile-enable-php-logfile/808 for more info

Integrity status for oC9+

Login as admin user into your ownCloud and access
http://example.com/index.php/settings/integrity/failed
paste the results here.

Hi,

for support/issues with the Synology packages you should contact the Synology support. The packages you're mentioning here are not provided by owncloud.org or anyone related to it.

they also shouldn't offer you an upgrade from oC 6 to oC8.x as this is an unsupported upgrade path from ownCloud side.

Depending on the oC 8 version they need to provide you the following upgrade path via packages (example 8.2 as target version):

oC 6.0.x -> latest 6.0.x -> latest 7.0.x -> latest 8.0.x -> latest 8.1.x -> latest 8.2.x

If that is not possible the package should be uninstall itself correctly which is only fixable by Synology or the package provider.