08-11-2022, 02:59 AM
You'll need to be more specific about exactly what you're trying to do as the details may matter. We have 3 bootloaders with differing capabilities and requirements:
tow-boot - configuration is baked in, so it should 'just work' with standard partitioning from distros that use the specific layout it needs. It won't work with distros that don't follow the layout it needs, or more complicated partitioning and multibooting options.
u-boot - can be configured so can be made to work in some situations where tow-boot can't, but as it doesn't have display support there are practical limitations to using it for multi-option situations.
pboot - from Megous, with a gui - very versatile but rarely used beyond the multi-OS SD image, and you'll need to do the config yourself.
The reason for overwriting (part of) u-boot (or whatever other bootloader) on the SD is to make sure it won't work as a bootloader, otherwise the bootloader on the emmc won't be used. The bootloader on the emmc must be capable of booting whatever you have on the SD though.
tow-boot - configuration is baked in, so it should 'just work' with standard partitioning from distros that use the specific layout it needs. It won't work with distros that don't follow the layout it needs, or more complicated partitioning and multibooting options.
u-boot - can be configured so can be made to work in some situations where tow-boot can't, but as it doesn't have display support there are practical limitations to using it for multi-option situations.
pboot - from Megous, with a gui - very versatile but rarely used beyond the multi-OS SD image, and you'll need to do the config yourself.
The reason for overwriting (part of) u-boot (or whatever other bootloader) on the SD is to make sure it won't work as a bootloader, otherwise the bootloader on the emmc won't be used. The bootloader on the emmc must be capable of booting whatever you have on the SD though.