"target/device/Atmel/arch-avre/kernel-headers-2.6.28.2" Make sure BR2_KERNEL_HEADERS_PATCH_DIR is enabled for 2.6.28 Set KERNEL_HEADERS_PATCH_DIR="target/device/Atmel/arch-avre/kernel-headers-2.6.28.2" for Atmel AVR32 targets and "valka"