Guideline issue

I cant manage to found it again, but i was pretty sure we cant cast spontaneous magic when we are wounded. But im looking everywhere in my Arm5 book, anyone have some clue ?

You get your wound penalty in the total but, as far as I'm aware, you can cast spontaneous magic while wounded.

Could you be thinking of the rule on p81 where fatiguing spontaneous magic, unlike formulaic, always uses a stress die?

Are you thinking of the issue of not being able to cast fatiguing spells (which includes most spontaneous spells) safely when wounded without incurring wound recovery rolls? (Page 178 of the main book).

That's not an absolute prohibition (you can do it, you just might make your wound get worse), and there are ways round even that problem, such as the Bind Wounds spell.

Exactly salutor. In order not to lose a magus based on a botch