Nintendo's 3DS OS and Switch 1+2 OS are bespoke and strictly microkernel-based (with the exception of DMA-330 CoreLink DMA handling on 3DS if you want to count is as such), and these have been deployed on hundreds of millions of commercially-sold devices.
Every +*general-puprose OS.
Nintendo's 3DS OS and Switch 1+2 OS are bespoke and strictly microkernel-based (with the exception of DMA-330 CoreLink DMA handling on 3DS if you want to count is as such), and these have been deployed on hundreds of millions of commercially-sold devices.