The Solderpad Hardware License
The Solderpad Hardware License is closely based on the Apache 2.0 software license (and in fact, if you adopt this license with a preamble, one option for the licensee is to choose to use unported Apache 2.0). The license differs from Apache mainly in that it covers additional forms of IP which are not covered by Apache (such as database extraction right), and also adjusts the terminology slightly to make it more understandable in a hardware context. It also works as a software license (arguably better than Apache, mainly because of its adoption of IP other than copyright, patent and trade mark).
The license is currently undergoing conformance testing and approval from a number of bodies, but since there is the option to relicense under Apache 2.0, you know that this licence is conformant with the criteria of any entity which has approved Apache 2.0 (including OSI and FSF).
THIS LICENCE IS A PERMISSIVE LICENCE, SO DO NOT USE IT IF YOU WANT TO AVOID THE POSSIBILITY OF VARIANTS OF YOUR WORK BECOMING NON-FREE.
Updated 08/03/12: removed “extraction” from phrase “database extraction rights” in the definition of Rights.