Firmware rollback for testing?

Is there any way to install an older firmware version, after one has upgraded a bulb? Since testing is an important part of software development, I’d like to be able to test my software against older firmware versions. (At least within the 2.x series; I’m fine with saying that 1.x is dead and buried.) Right now I have one bulb with 2.1 and one bulb with 2.0. I’d like to upgrade my 2.0 bulb to 2.1, but if that’s truly a one-way operation, I’m more reluctant. As more 2.x versions are released in the future, the situation will only become worse, testing-wise.

Currently we have not released a public method for downgrading. We do have one that we use internally to LIFX but it has a fairly high failure rate resulting in bricked bulbs. Getting complete backwards and forwards compatibility for upgrades of an embedded system is really hard. Its not really a priority for us and I doubt if it’ll ever be fixed to a point where it can be publicly released.