I'm looking at u-boot source code, and see a huge amount of hardware drivers, used only for the loader. On the other side, modern Linux kernels eat a more than half of RAM on cheap embedded modules like HLK-R04. Linux kernels have got fat.  I believe it would be easier to remove modules, and avoid the large task of coding. What u-boot does not have Memory managementVirtual MemoryMultitaskingApplication are compiled and linked into the u-boot binary. I'd first put the linux kernels on a diet. Lit all the modules, describe each one's use, and then decide on include/exclude each kernel module. Tedious? yes. Coding? No. Testing? Yes but less than new code.

Duncan Hare

714 931 7952