New Security settings in INF donot take effect on mahcine where driver already exists

Hi ,

I have a system where i have installed my driver with following security settings.
HKR,Security,"D:P(A;;GA;;;SY)(A;;GA;;;BA)

But we had a new requirement for application to be able to access this driver even in non-admin mode and by untrusted applications. So we made following security changes.

HKR,Security,“D:P(A;;GA;;;SY)(A;;GRGWGX;;;BA)(A;;GRGWGX;;;WD)(A;;GRGWGX;;;RC)”

but now the problem is if you try to update driver on a system where the driver is already installed the new security settings do not take effect. but on a fresh system where this driver is never installed new security settings seems to be working.

Please suggest how to fix this on a machine which already has the driver installed.

Thanks,
Ramana