Today I've received the Samsung stick that is one of the recommended WiFi sticks. It looks like when setting M20d up to use an existing WiFi network, it is only able to connect to WiFi networks on channel 1! I tried different channels but was only able to connect the M20d on channel 1. When using the standalone mode, all other channels work as well, so it is not an issue of the stick.
Is this a known issue? Has somebody else experienced this?