The Ethiopian scale consists of 7 different notes. Notice how that when you ascend the scale Bb, Eb, and F natural notes are played, and when you descend the scale F#, E natural, and B natural notes are played. This concept is also seen in the Melodic Minor Scale.
1, 2, b3, 4, 5, b6, b7,
Formula: WS, HS, WS, WS, HS, WS, WS