2017 F/L S3 went in to Audi for service and I asked if there were any software/firmware upgrades and was advised not. Have recently noticed losing the bass/treble settings and satnav/phone volume resetting to default. Went back to Audi last week and car booked in for this Wednesday. Went back in with detailed description of the problem which was shared with one of the technicians. He was aware of the issues and would check my MMI version (0170). The Manager came back to me after an hour of so and said they have the upgrade (0235) and said it would take about an hour and they can do it while I wait, so I agreed. Nearly 2 hours later, he came back and said the upgrade had failed to complete fully, which may have been due to their systems. He advised Audi technical were due on site to upgrade their systems the next day. Car booked in for 3rd September. Checked MMI and now on version 0235 and Subwoofer control now available. What was interesting, was the manager saying the Audi will only upgrade software if you actually report the relevant problems to them, i.e. they will only upgrade my MMI from 0170 to 0235 if I give them a description of the actual problem relating to Audio settings. Will update further as necessary.