Tried to tack this onto a similar post....

I get a similar error as Mugiwaxar when I use this with Spaceblock. It is with the coal icon though. I have a few mods installed but the error goes away when I don't load reverse-factory with spaceblock, leaving all the other mods being loaded.
<Error>
Failed to load mods: The given sprite rectangle (left_top=0x0, right_bottom=64x64) is outside the actual sprite size (left_top=0x0, right_bottom=32x32). If this is being used as an icon you may need to define the icon_size properly:'base/graphics/icons/coal.png'

Mods to be disabled:
*reverse-factory
</Error>

Sorry about the long wait, but this is.. unique. Spaceblock seems to be adding new recipes that don't really fit with the logic of my mod, and it ends up with conflicting icon sizes. The icon being used is 32, but I think the original icon was 64, and the icon_size was never overwritten (likely because the default size is 32, when none is defined). Something like that.

Manually setting the icon size to 32 fixes the error... Ah, but the recipe is simply turning 6 "ore" into 5 "ore". So easier to just disable the recipe entirely for this mod. Alright, should be fixed as of 6.1.21