While doing a 1.13.x build on arm64 (ODROID-C2) using:
sudo make build
In step 28, after downloading 2 layers (of 5), it encounters:

curl: (22) The requested URL returned error: 401 Unauthorized

and the build failed. See partial output below.

Step 28 : RUN ./contrib/download-frozen-image-v2.sh /docker-frozen-images aarch64/buildpack-deps:jessie@sha256:6aa1d6910791b7ac78265fd0798e5abd6cb3f27ae992f6f960f6c303ec9535f2 aarch64/busybox:latest@sha256:b23a6a37cf269dff6e46d2473b6e227afa42b037e6d23435f1d2bc40fc8c2828 aarch64/debian:jessie@sha256:4be74a41a7c70ebe887b634b11ffe516cf4fcd56864a54941e56bb49883c3170 aarch64/hello-world:latest@sha256:65a4a158587b307bb02db4de41b836addb0c35175bdc801367b1ac1ddeb9afda
---> Running in d139f3f0e6b5
warning: 'aarch64/buildpack-deps:jessie@sha256:6aa1d6910791b7ac78265fd0798e5abd6cb3f27ae992f6f960f6c303ec9535f2' uses schemaVersion '1'
this script cannot (currently) recreate the 'image config' to put in a 'manifest.json' (thus any schemaVersion 2+ images will be imported in the old way, and their 'docker history' will suffer)

Downloading 'aarch64/buildpack-deps:jessie@sha256:6aa1d6910791b7ac78265fd0798e5abd6cb3f27ae992f6f960f6c303ec9535f2' (5 layers)...
######################################################################## 100.0%
######################################################################## 100.0%

curl: (22) The requested URL returned error: 401 Unauthorized
The command '/bin/sh -c ./contrib/download-frozen-image-v2.sh /docker-frozen-images aarch64/buildpack-deps:jessie@sha256:6aa1d6910791b7ac78265fd0798e5abd6cb3f27ae992f6f960f6c303ec9535f2 aarch64/busybox:latest@sha256:b23a6a37cf269dff6e46d2473b6e227afa42b037e6d23435f1d2bc40fc8c2828 aarch64/debian:jessie@sha256:4be74a41a7c70ebe887b634b11ffe516cf4fcd56864a54941e56bb49883c3170 aarch64/hello-world:latest@sha256:65a4a158587b307bb02db4de41b836addb0c35175bdc801367b1ac1ddeb9afda' returned a non-zero code: 22
Makefile:96: recipe for target 'build' failed
make: *** [build] Error 22