RZ/N1D U-Boot: SRAM load address and reading cm3 image

Hello,

I have a couple of questions I was hoping to get some help with...

1. Why is the U-Boot SRAM load address at 0x200A0000 and not 0x20000000?

2. When loading a cm3 image into the SRAM instruction RAM area at 0x04000000, are there any limitations around the size of the cm3 image or accessing this upper 1MB area of SRAM (is U-boot actually executing out of the upper 1MB)? 

I'm seeing U-boot crash when I specify a cm3 image size larger than the 0x80000...

Thanks in advance,

Matt