So to confirm what you said when playing over a minor key, I can still use the major scale without flatting any note or without raising any note. The same applies with other modes. Is that correct?
Yes. Minor keys use the same scale patterns and chords as major keys, you just phrase everything around a different scale degree like vi. Em is simply G major scale patterns. Am is C major patterns, etc. This is covered in Fretboard Theory Chapter 7: Roots, Keys and Applying Scales.
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