Bootloader for boot from USB pendrive


In rkdeveloptool I don’t see such, but maybe some compile is needed.

Anyone knows some small code which I could place on may uSD card in first sector (MBR) to boot from USB pendrive?

Let’s say USB pendrive would be exact copy of booting/working uSD card and I want to boot and work from it, but only need the code for uSD card.