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How can I reserve a portion of SDRAM, say 4 bytes, to pass a flag between U-Boot and the Linux kernel so that this reserved memory location is not initialized by the linker and the value preserved after a warm boot? I'm trying to avoid using bootargs to minimize wear of the NAND flash used in an embedded application. My question could be considered an extension to the solution provided by: How to detect cold boot versus warm boot on an ARM processor? I have built u-boot.lds with the linker script below and built it with: -fno-zero-initialized-in-bss without success. OUTPUT_FORMAT("elf32-littlearm", "elf32-littlearm", "elf32-littlearm") OUTPUT_ARCH(arm) ENTRY(_start) SECTIONS { . = 0x00000000; . = ALIGN(4); .text : { cpu/arm926ejs/start.o (.text) *(.text) } . = ALIGN(4); .rodata : { *(SORT_BY_ALIGNMENT(SORT_BY_NAME(.rodata*))) } . = ALIGN(4); .data : { *(.data) } . = ALIGN(4); .got : { *(.got) } . = .; __u_boot_cmd_start = .; .u_boot_cmd : { *(.u_boot_cmd) } __u_boot_cmd_end = .; . = ALIGN(4); __bss_start = .; _U_BOOT_FLAG = .; . = . + 4; .bss (NOLOAD) : { *(.bss) . = ALIGN(4); } _end = .; } Any ideas?

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