How to develop software that could be put onto a thumb drive and most modern x86 systems (or old ones if 64-bit isn't required) could boot and run it?
What kind of emulator or VM is required? Want to be able to iterate as quickly as possible in standard linux dev environment then occasionally reboot to test it for real.
gcc is likely fine for the application, similar to the
Probably very similar to any bootloader application.
Can vga and text mode graphics be used in a general way?
What about sound output?
The raspberry pi is an easier application for similar goals, probably because the arm is less complicated (less legacy memory modes to be compatible with) and a single pi version could be targeted, though that is perhaps too easy.