I have an ancient Samsung with a flip out keyboard and it picks up right where it left off. Occasionally it may take a minute to complete the bluetooth handshake but that is rare.
Generally, if it doesn't sync immediately, it will sync within 10 seconds of the car being on.
My car has never been back to dealership since I took delivery of it on August 22 of last year, so if your car is older than that, it may be an update, if it's newer, well I have no clue.
99 Chevrolet Camaro Z28 M6 - 6.676 @ 103 in 1/8, 10.512 @ 130.2 on street tires, H/C/I
93 Eagle Talon TSI AWD 5spd - Built 6 Bolt, 16G Evo3, HKS 272 Cams - under construction