Map update is simple; they're on DVD in a DVD player somewhere in your car. The Nav player was in the boot of my A8 but I don't know where it is in an A5. In 2007 Europe maps were on 1 DVD; the maps were issued yearly on 1 DVD until 2013. From 2014 until 2018 [last year of issue for 2G] they were on 2 DVDs, Europe West [includes UK] and Europe East [doesn't include UK]. You just need to find [on Ebay?} 2G Navigation DVDs. Update is simple; take out old DVD and insert new DVD. The MMI screen will detect the new map and ask you to confirm that you want to update.
MMI update is via CD, so no AMI doesn't create a problem. Yout MMI version - B8-HU 51.7.0 0741 - is version 5170, issued by Audi in Year 2007 Week 41. There's only one later version - 55.7.0 [Year 2008 Week 38] and that may not give you much extra as I don't believe it changed much. If you haven't got problems, it may not be worth updating. There are two types of update in each level; firstly the MMI code might be changed to fix problems or add functions to the MMI system and secondly, updated firmware may be provided for your MMI devices. If you tell me what you've got on the MMI loop I can tell you if any new firmware was supplied on 5570. [See attached text file to see what 'stuff' you've got on your MMI loop.]
