在BB Black u-boot printevn下：
mtdids=nand0=omap2-nand.0
mtdparts=mtdparts=omap2-nand.0:128k(SPL),128k(SPL.backup1),128k(SPL.backup2),128k(SPL.backup3),1920k(u-boot),128k(u-boot-env),5m(kernel),-(rootfs)
但是在am335x_evm.h中：
#define MTDIDS_DEFAULT "nand0=nand.0"
#define MTDPARTS_DEFAULT "mtdparts=nand.0:" \
"128k(NAND.SPL)," \
"128k(NAND.SPL.backup1)," \
"128k(NAND.SPL.backup2)," \
"128k(NAND.SPL.backup3)," \
"256k(NAND.u-boot-spl-os)," \
"1m(NAND.u-boot)," \
"128k(NAND.u-boot-env)," \
"128k(NAND.u-boot-env.backup1)," \
"8m(NAND.kernel)," \
"-(NAND.file-system)"
问题：am335x_evm.h中布局怎么这么奇怪，"256k(NAND.u-boot-spl-os)," \是什么？
u-boot不是在0x8000处吗？
