Steps To Reproduce:
Follow the steps mentioned in https://www.chromium.org/chromium-os/developer-guide to build a chromium os image with minilayout option for arm-generic board

Expected Result:
Build completes successfully

Actual Result:
build_image fails with below logs:

INFO    : Generating license credits page. Time:

real    0m14.338s
user    0m6.036s
sys     0m0.208s
16:14:02: INFO: Searching for unused gconv files defined in /mnt/host/source/src/build/images/arm-generic/R58-9210.0.2017_01_23_1609-a1/rootfs/usr/lib/gconv/gconv-modules
16:14:03: INFO: Will search for 1131 strings in 34 files
16:14:04: INFO: Done. Using 56 gconv modules. Removed 190 unused modules (14452.4 KiB) and 2 unused dependencies (202.7 KiB)
/mnt/host/source/src/scripts/build_library/base_image_util.sh: line 241: /mnt/host/source/src/platform/vboot_reference/scripts/image_signing/insert_container_publickey.sh: No such file or directory
INFO    : Unmounting image from /mnt/host/source/src/build/images/arm-generic/R58-9210.0.2017_01_23_1609-a1/stateful and /mnt/host/source/src/build/images/arm-generic/R58-9210.0.2017_01_23_1609-a1/rootfs
Cleaning up /usr/local symlinks for /mnt/host/source/src/build/images/arm-generic/R58-9210.0.2017_01_23_1609-a1/stateful/dev_image
An error occurred in your build so your latest output directory is invalid.
---

How frequently does this problem reproduce? 
Always

What is the impact to the user, and is there a workaround? If so, what is
it?
Can get around this issue by checking out "chromeos-base/vboot_reference" project as below:
cros_workon --board=${BOARD} start chromeos-base/vboot_reference
repo sync chromiumos/platform/vboot_reference
cros_workon --board=${BOARD} stop chromeos-base/vboot_reference
./build_image --board=${BOARD} --noenable_rootfs_verification test


Please provide any additional information below. Attach a screen shot or
log if possible.
The issue looks generic enough to impact other boards as well.