This paper is a great read for anyone researching or developing open source hardware.

From Highlights:

• Open Source Technology Readiness Levels assess openness maturity of technologies. • OSTRLs include nine assessment levels of product and process openness maturity. • Other readiness frameworks can be used with OSTRLs for broader adoption assessment. • OSTRLs can assess existing real-world ecosystems adopting open source technology. • OSTRLs support strategic decision-making and future research in sustainable systems.