diff --git a/build-all b/build-all
index 939f4a2..e8f2226 100755
--- a/build-all
+++ b/build-all
@@ -1,18 +1,18 @@
 #!/usr/bin/env bash
-set -eux
-# Build all archs (that we care the most about).
-# Will take forever from a clean repo, this is most useful
-# after pulling the repository to do an incremental build
-# then quickly test out all the setups.
+set -eu
+archs='x86_64 arm aarch64'
 gem5=-g
-while getopts G OPT; do
+while getopts A:G OPT; do
   case "$OPT" in
+    A)
+      archs="$OPTARG"
+      ;;
     G)
       gem5=
       ;;
   esac
 done
 shift "$(($OPTIND - 1))"
-for arch in x86_64 arm aarch64; do
+for arch in $archs; do
   ./build -a "$arch" -klq $gem5 "$@"
 done