diff --git a/debian/changelog b/debian/changelog
index 1a3a082..1d642cb 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -4,6 +4,7 @@ shim (15+1533136590.3beb971-2) UNRELEASED; urgency=medium
   * Update VCS to point to salsa.
   * Fix debian/rules syntax for arm64 build.
   * Enable build for i386.
+  * Ensure DEB_HOST_ARCH is set even if not present in the environment.
 
  -- Steve Langasek <vorlon@debian.org>  Sun, 10 Feb 2019 00:15:19 -0800
 
diff --git a/debian/rules b/debian/rules
index a75c1d1..37df25a 100755
--- a/debian/rules
+++ b/debian/rules
@@ -12,6 +12,8 @@ else
 	distributor=debian
 endif
 
+DEB_HOST_ARCH ?= $(shell dpkg-architecture -qDEB_HOST_ARCH)
+
 ifeq ($(DEB_HOST_ARCH),amd64)
 export EFI_ARCH := x64
 endif