[U-Boot] No BOOT_FROM tag build error

[Fabio Estevam]

Hi,

My colleague Breno reported an issue with vf610twr_defconfig in U-Boot mainline.

Sometimes it fails like this:

  CAT     u-boot-dtb.bin
  COPY    u-boot.dtb
  COPY    u-boot.bin
  CFGS    board/freescale/vf610twr/imximage.cfg.cfgtmp
  CFGS    board/freescale/vf610twr/imximage.cfg.cfgtmp
  MKIMAGE u-boot-dtb.imx
Error: No BOOT_FROM tag in board/freescale/vf610twr/imximage.cfg.cfgtmp
arch/arm/mach-imx/Makefile:100: recipe for target 'u-boot-dtb.imx' failed
make[1]: *** [u-boot-dtb.imx] Error 1
Makefile:911: recipe for target 'u-boot-dtb.imx' failed
make: *** [u-boot-dtb.imx] Error 2
make: *** Waiting for unfinished jobs....
  MKIMAGE u-boot.imx
rm u-boot.imx

After this fails, if I run 'make -j4' then the build successfully
completes in the second attempt.

I am able to reproduce it (not 100% though) with these steps:

make mrproper
make vf610twr_defconfig
make -j4

If I use just 'make' to build with a single core I never see the failure.

Recently Thomas also reported the same problem in the Buildroot autobuilder :
http://lists.busybox.net/pipermail/buildroot/2018-March/215036.html

Does anyone have any idea on how to properly fix this issue?

Thanks,

Fabio Estevam