Default [Q] samsung galaxy custom rom

phone is samsung galaxy ring(sorry for not listing in name of thread)

'ok i wanted to know if anyone knows what "custom" rom samsung provided with the phone.

or if anyone knows a good stable rom for this phone.

also does installing the "custom" rom samsung provides void my warranty?

and to download the "custom" rom provided with the phone you press volume down button and power during boot up.
linked "custom" rom is set by samsung

as always thanks in advance for any information provided.