Loading U-Boot code at low addresses (begining of RAM) can cause problem.
Function get_ram_size() detects size of RAM writing pattern
between 256MB and 0MB. It takes highest address and divides
it by 2 on every iteration. It's possible that this function will
destroy code which is executed at the moment (writing detection pattern).
U-Boot will probably not occupy more than 2MB, so it's safe to
load code between 4MB and 8MB (excluding 0x400000 and 0x800000).
Loading U-Boot at address 0x500000 eliminates problem with get_ram_size()
function.
Signed-off-by: Marcin <marcin.mielczarczyk@gmail.com>
Marcin