diff --git a/Dockerfile b/Dockerfile
index f1920d4..c6153d3 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -7,7 +7,11 @@ RUN apt-get update && apt-get install -y \
     libc6-dev \
     python3
 
-RUN git clone -c feature.manyFiles=true --depth=2 https://github.com/spack/spack.git
+RUN git clone \
+    -c feature.manyFiles=true \
+    --depth=2 \
+    --branch prereleases/v1.0.0-alpha.1 \
+    https://github.com/spack/spack.git
 
 ENV PATH="${PATH}:/spack/bin"
 
diff --git a/spack.yaml b/spack.yaml
index 6d277f4..e711d45 100644
--- a/spack.yaml
+++ b/spack.yaml
@@ -5,7 +5,7 @@
 spack:
   specs:
     - coreutils
-    - gcc+binutils
+    - gcc+binutils@11
     - git
     - gmake
     - patch
@@ -33,5 +33,7 @@ spack:
   packages:
     all:
       target: [x86_64_v3]
+    gcc:
+      buildable: True
   concretizer:
     unify: true