BRB Official Update Version 1.7 p. 8:
Q: What are ‘magical attacks’? (p68)
A: All attacks made by spells and magic items are considered to be magical attacks, as are all attacks that are specifically noted as being magical attacks. Shots fired from magical items are also considered to be magical attacks, unless their description specifically states otherwise. Hits inflicted by rolls on the Miscast table are treated as magical attacks.
Unless specified as such, Flaming Attacks are not magical. The Banner of the Eternal Flame or the part of Soulfire that gives the Flaming Attacks special rule, do not cause attacks themselves, and thus the Flaming Attacks are not magical. However, the hits caused by (the second part of )the Soulfire spell are magical.
