A página DULG DebuggingUBoot tem isto a dizer (a "realocação" da qual ele fala está se copiando do flash para RAM).
Outras leituras do texto parecem indicar que ele depende do processador ou da placa e que você pode ter que verificar a origem do U-Boot para ter certeza.For debugging U-Boot after relocation we need to know the address to which U-Boot relocates itself to. When no exotic features like PRAM are used, this address usually is - CONFIG_SYS_MONITOR_LEN. In our example with 16MB RAM and CONFIG_SYS_MONITOR_LEN = 192KB this yields the address 0x1000000 - 0x30000 = 0xFD0000.
Em relação ao Guruplug :
On the RAM side, u-Boot has the first 8 megabytes reserved. The rest is free. Some developer’s will load kernels and filesystems at 0×800000 for programming to flash. Another common spot is at the 100 megabyte boundary (or offset 0×640000).
Depending on your version of U-Boot commands may be available to put a string somewhere in free RAM and then hunt the rest of RAM for that string, revealing the approximate location of U-Boot in memory.