Draytek Vigor 2820
From BE Usergroup Technotes
Annex M support confirmed working under firmware 3.2.0.
1. To set up as "Annex M", access the router's web portal and navigate to WAN > Internet Access > WAN1, change the "modulation" pull down option to "ADSL2+ annex M", click OK and wait for the router to reboot:
2. The Online Status page should then show the new sync speed (but oddly shown as "ETSI annexC" on older firmwares. It shows correctly on recent firmware versions):


