[U-Boot] Beaglebone Black U-boot won't buid - THUMB instruction issue

[John Babrick]

Hello - I am trying to work through the book "Mastering Embedded Linux
Programming" by Chris Simmonds, and trying to work through building u-boot
after having built the cross toolchain. I am running into an error when I
try to build u-boot, any ideas?

johann at mars:~/uboot-work/u-boot$ make
CROSS_COMPILE=arm-cortex_a8-linux-gnueabihf- am335x_evm_defconfig
#
# configuration written to .config
#
johann at mars:~/uboot-work/u-boot$ make
CROSS_COMPILE=arm-cortex_a8-linux-gnueabihf-
scripts/kconfig/conf  --silentoldconfig Kconfig
  CHK     include/config.h
  UPD     include/config.h
  CFG     u-boot.cfg
  GEN     include/autoconf.mk
  GEN     include/autoconf.mk.dep
  CFG     spl/u-boot.cfg
  GEN     spl/include/autoconf.mk
  CHK     include/config/uboot.release
  CHK     include/generated/version_autogenerated.h
  CHK     include/generated/timestamp_autogenerated.h
  UPD     include/generated/timestamp_autogenerated.h
*  CC      lib/asm-offsets.s*
*cc1: warning: target CPU does not support THUMB instructions*
*  CHK     include/generated/generic-asm-offsets.h*
*  CC      arch/arm/lib/asm-offsets.s*
*cc1: warning: target CPU does not support THUMB instructions*
  CHK     include/generated/asm-offsets.h
  HOSTCC  scripts/dtc/dtc.o
  HOSTCC  scripts/dtc/flattree.o
  HOSTCC  scripts/dtc/fstree.o
  HOSTCC  scripts/dtc/data.o
  HOSTCC  scripts/dtc/livetree.o
  HOSTCC  scripts/dtc/treesource.o
  HOSTCC  scripts/dtc/srcpos.o
  HOSTCC  scripts/dtc/checks.o
  HOSTCC  scripts/dtc/util.o
  SHIPPED scripts/dtc/dtc-lexer.lex.c
  SHIPPED scripts/dtc/dtc-parser.tab.h
  HOSTCC  scripts/dtc/dtc-lexer.lex.o
  SHIPPED scripts/dtc/dtc-parser.tab.c
  HOSTCC  scripts/dtc/dtc-parser.tab.o
  HOSTLD  scripts/dtc/dtc
  HOSTCC  tools/mkenvimage.o
  HOSTCC  tools/lib/crc32.o
  HOSTLD  tools/mkenvimage
  HOSTCC  tools/common/bootm.o
  HOSTCC  tools/lib/fdtdec.o
  HOSTCC  tools/fit_image.o
  HOSTCC  tools/image-host.o
  HOSTCC  tools/dumpimage.o
  HOSTLD  tools/dumpimage
  HOSTCC  tools/mkimage.o
  HOSTLD  tools/mkimage
  CC      arch/arm/cpu/armv7/cache_v7.o
*cc1: warning: target CPU does not support THUMB instructions*
*{standard input}: Assembler messages:*
*{standard input}:42: Error: selected processor does not support `dsb sy'
in ARM mode*
*{standard input}:46: Error: selected processor does not support `isb sy'
in ARM mode*
*{standard input}:240: Error: selected processor does not support `dsb sy'
in ARM mode*
*{standard input}:244: Error: selected processor does not support `isb sy'
in ARM mode*
*{standard input}:368: Error: selected processor does not support `dsb sy'
in ARM mode*
*{standard input}:460: Error: selected processor does not support `dsb sy'
in ARM mode*
*{standard input}:464: Error: selected processor does not support `isb sy'
in ARM mode*
*{standard input}:594: Error: selected processor does not support `dsb sy'
in ARM mode*
*scripts/Makefile.build:278: recipe for target
'arch/arm/cpu/armv7/cache_v7.o' failed*
make[1]: *** [arch/arm/cpu/armv7/cache_v7.o] Error 1
Makefile:1363: recipe for target 'arch/arm/cpu/armv7' failed