LOR from a school you're not at?

[Laxattack09]

If I went to school A for a year, but then transferred to school B, would I be foolish to ask a professor from school A that I'm really close with and that can write me a great LOR to do just that? Or should I try to get all my LOR's from my graduating institution. So far I have one from B and am up in the air as to whether or not to ask the guy from school A. Thanks.

[t L]

I don't think it really matters.  Do it.