building of linux-signed package failing on arm64

dpkg-buildpackage
-----------------

dpkg-buildpackage: info: source package linux-signed-aws
dpkg-buildpackage: info: source version 4.15.0-1119.126
dpkg-buildpackage: info: source distribution bionic
 dpkg-source --before-build linux-signed-aws-4.15.0
dpkg-buildpackage: info: host architecture arm64
dpkg-source: info: using options from linux-signed-aws-4.15.0/debian/source/options: --diff-ignore --tar-ignore
 fakeroot debian/rules clean
sed <debian/control.stub >debian/control \
 -e "s/@ABI@/4.15.0-1119/g" \
 -e "s/@UNSIGNED_SRC_PACKAGE@/linux-aws/g" \
 -e "s/@UNSIGNED_SRC_VERSION@/4.15.0-1119.126/g" \
 -e 's/@SRCPKGNAME@/linux-signed-aws/g' \
 -e 's/@HEADERS_COMMON@/linux-aws-headers-4.15.0-1119/g' \
 -e 's/@HEADERS_ARCH@/linux-headers-4.15.0-1119-aws/g'
rm -rf ./4.15.0-1119.126 UNSIGNED SIGNED
rm -f debian/linux-image-*.install \
 debian/linux-image-*.preinst \
 debian/linux-image-*.prerm \
 debian/linux-image-*.postinst \
 debian/linux-image-*.postrm
rm -f debian/kernel-signed-image-*.install
dh clean
   dh_clean
 debian/rules build-arch
dh build-arch
   dh_update_autotools_config -a
   debian/rules override_dh_auto_build
make[1]: Entering directory '/<<PKGBUILDDIR>>'
./download-signed "linux-headers-4.15.0-1119-aws" "4.15.0-1119.126" "linux-aws"
Downloading http://ppa.launchpad.net/canonical-kernel-team/ppa/ubuntu/dists/bionic/main/signed/linux-aws-arm64/4.15.0-1119.126/SHA256SUMS ... found
Downloading http://ppa.launchpad.net/canonical-kernel-team/ppa/ubuntu/dists/bionic/main/signed/linux-aws-arm64/4.15.0-1119.126/signed.tar.gz ... found
Extracting 4.15.0-1119.126 ...
Extracting 4.15.0-1119.126/control ...
Extracting 4.15.0-1119.126/control/options ...
mkdir SIGNED
( \
 cd "4.15.0-1119.126" || exit 1; \
 for s in *.efi.signed; do \
  [ ! -f "$s" ] && continue; \
  base=$(echo "$s" | sed -e 's/.efi.signed//'); \
  ( \
   vars="${base}.efi.vars"; \
   [ -f "$vars" ] && . "./$vars"; \
   if [ "$GZIP" = "1" ]; then \
    gzip -9 "$s"; \
    mv "${s}.gz" "$s"; \
   fi; \
  ); \
  chmod 600 "$s"; \
  ln "$s" "../SIGNED/$base"; \
 done; \
 for s in *.opal.sig; do \
  [ ! -f "$s" ] && continue; \
  chmod 600 "$s"; \
  base=$(echo "$s" | sed -e 's/.opal.sig//'); \
  cat "$base.opal" "$s" >"../SIGNED/$base"; \
 done; \
 for s in *.sipl.sig; do \
  [ ! -f "$s" ] && continue; \
  base=$(echo "$s" | sed -e 's/.sipl.sig//'); \
  cat "$base.sipl" "$s" >"../SIGNED/$base"; \
  chmod 600 "../SIGNED/$base"; \
 done \
)
make[1]: Leaving directory '/<<PKGBUILDDIR>>'
 fakeroot debian/rules binary-arch
dh binary-arch
   dh_testroot -a
   dh_prep -a
   debian/rules override_dh_auto_install
make[1]: Entering directory '/<<PKGBUILDDIR>>'
for signed in "SIGNED"/*; do \
 flavour=$(echo "$signed" | sed -e "s@.*-4.15.0-1119-@@"); \
 instfile=$(echo "$signed" | sed -e "s@[^/]*/@@" -e "s@-4.15.0-1119-.*@@"); \
 verflav="4.15.0-1119-$flavour"; \
         \
 package="kernel-signed-image-$verflav-di"; \
 echo "$package: adding $signed"; \
 echo "$signed boot" >>"debian/$package.install"; \
         \
 package="linux-image-$verflav"; \
 echo "$package: adding $signed"; \
 echo "$signed boot" >>"debian/$package.install"; \
         \
 ./generate-depends linux-image-unsigned-$verflav 4.15.0-1119.126 \
  linux-image-$verflav \
  >>"debian/linux-image-$verflav.substvars"; \
         \
 for which in postinst postrm preinst prerm; do \
  template="debian/templates/image.$which.in"; \
  script="debian/$package.$which"; \
  sed -e "s/@abiname@/4.15.0-1119/g" \
      -e "s/@localversion@/-$flavour/g" \
      -e "s/@image-stem@/$instfile/g" \
   <"$template" >"$script"; \
 done; \
 echo "interest linux-update-4.15.0-1119-$flavour" \
  >"debian/$package.triggers"; \
done
kernel-signed-image-4.15.0-1119-SIGNED/*-di: adding SIGNED/*
/bin/sh: 8: cannot create debian/kernel-signed-image-4.15.0-1119-SIGNED/*-di.install: Directory nonexistent
linux-image-4.15.0-1119-SIGNED/*: adding SIGNED/*
/bin/sh: 12: cannot create debian/linux-image-4.15.0-1119-SIGNED/*.install: Directory nonexistent
/bin/sh: 14: cannot create debian/linux-image-4.15.0-1119-SIGNED/*.substvars: Directory nonexistent
/bin/sh: 21: cannot create debian/linux-image-4.15.0-1119-SIGNED/*.postinst: Directory nonexistent
/bin/sh: 21: cannot create debian/linux-image-4.15.0-1119-SIGNED/*.postrm: Directory nonexistent
/bin/sh: 21: cannot create debian/linux-image-4.15.0-1119-SIGNED/*.preinst: Directory nonexistent
/bin/sh: 21: cannot create debian/linux-image-4.15.0-1119-SIGNED/*.prerm: Directory nonexistent
/bin/sh: 26: cannot create debian/linux-image-4.15.0-1119-SIGNED/*.triggers: Directory nonexistent
debian/rules:81: recipe for target 'override_dh_auto_install' failed
make[1]: *** [override_dh_auto_install] Error 2
make[1]: Leaving directory '/<<PKGBUILDDIR>>'
debian/rules:45: recipe for target 'binary-arch' failed
make: *** [binary-arch] Error 2
dpkg-buildpackage: error: fakeroot debian/rules binary-arch subprocess returned exit status 2