I am in the same situation. Although I need others than ios 58. I need a ios 53 (rev 5919) and an ios 33 (rev 3864). I've done all the research I can and all I found is that I need these files in order to progress, but I looked all over the internet and can not find public ios's of these types. I posted this reply here because making a whole separate one of the similar subject would be pointless. (I'm guessing someone PMs these too us since its not public).
If someone one can help that will be great
(Sorry that this post cant help you Seleir. I just need help as well)