Re: Well currently the problem with ARM is not the CPU
There are ways round this, like Yocto Project.
I've got code that runs on various x86 and ARM platforms and I've not had to mess with any bootloaders with the BSP side being managed by board vendors.
A bit of configuration file work to adapt the kernel to the platforms, but that's more to do with removing the virtually infinite number of X86 drivers that aren't needed on the x86 platform in order to reduce the image size and boot times.