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When I get the memory map from UEFI, it returns valid ranges, but the memory marked as EfiConventionalMemory (7) has the attribute 0xF - this means uncacheable, write combining, write-through and write-back. Conventional memory should obviously be write-back. I've heard (but don't know how to confirm) that the memory attributes might be wrong for conventional memory - and these are clearly garbage.

Has anyone else seen this? Am i supposed to just ignore the attributes for conventional memory?

Those attributes look correct to me. The attributes indicate capabilities, and ordinary RAM is capable of using any of those four caching modes. Yes, you usually want write-back, but the other three choices are still valid and occasionally necessary (e.g. buffers for HD Audio devices).

I was under the impression that these were telling me how to map them. I guess i should be using the Memory Type instead?

You're supposed to use both. The memory type tells you what you're mapping, and the attributes tell you how you're allowed to map it.

I can't think of any situation where ordinary RAM wouldn't have the write-back attribute, though, so it might be okay to ignore the attributes in this case.