[U-Boot-Users] DataFlash on my SBC is failed, can i boot u-boot ?

[nm]

Hi *,
is it possible to boot u-boot if i dont' have DataFlash ?
some thing like :

puts("Please upload your u-boot.bin");
rxmodem(char *)0x21F80000));
asm("ldr pc, =0x21F80000");

Thanks for help,

nm.