For the magicians (from HMRE) who can do spontaneous magic (I especially think about gruagachan... i think they are, with learned magician at a lower level, the only one who can do it).
We know that hermetic magi CAN'T do spontaneous magic while having a wound malus (thus, an hermetic magic with an active endurance of the berserker can still do it).
But what about hedge magician in the same situation.
In casu, it's a gruagach heavily wounded.
I can't find any indication of either he can or can't.
I just checked very fast but I didn't find anything saying so. In our sagas, magi used spontaneous magic plenty of times when wounded, but afaik it could be a rule we missed.
Page 178-179: activities while injured. If your wound poenalty goes above -2 (more than 2 light wounds) you cannot cast spont spells. If he is at -1 or -2 wound penalty he can only cast spontaneous spells that do not cost fatigue (so he divides by 5)
We find those limitations overly harsh, and do not use them IMS, but hey.
For HM, I would apply the same criteria as for hermetics. The difference is that hedgies (specially gruagachan) can have dozens of low level spells (learn spells for diameter instead of sun duration, for example) boosted by their extremely flexible formulaic magic. As such, that is not a very big limitation.
Serfs Parma, but my understanding is that the "can't cast spont spells with wounds penalties of -2 or more" rule only applies once the combat is over. So, if you were involved in a situation and you were not wounded when it started, you can cast spont spells until it is over, even if you have taken a heavy wound in the middle of it.
According to ArM5 page 178 hermetic magi CAN do spontaneous magic while having a wound malus:
Any character who does more than his injuries allow must make an immediate Recovery roll for his most serious wound. This roll can result in a wound worsening, but not in improvement.
If a hermetic magus is casting a spell which costs fatigue (this is possible with formulaic magic as well, page 81),
he has to make an immediate Recovery roll.
But that is easily forgotten.
I did not post the whole rules, just a bird's eye overview of it.