Upgrade from 1.8 isn't smooth, after first core uprgades we are bounced to upgradesettings, then

Access denied
Stack trace:
line 5727 of lib/weblib.php: call to debugging()
line 3839 of lib/adminlib.php: call to error()
line 12 of admin/upgradesettings.php: call to admin_externalpage_setup()

Then we continue with the module/block upgrades, and we next get:

Sorry, but you do not currently have permissions to do that (Change site configuration)

Stack trace:
line 5727 of lib/weblib.php: call to debugging()
line 5788 of lib/weblib.php: call to error()
line 836 of lib/accesslib.php: call to print_error()
line 529 of admin/index.php: call to require_capability()