diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index e2466db57..ca6c5df5f 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -28,7 +28,7 @@ jobs:
         include:
           - target:
               os: linux
-            builder: ubuntu-18.04
+            builder: ubuntu-20.04
           - target:
               os: macos
             builder: macos-10.15
@@ -47,8 +47,8 @@ jobs:
         if: runner.os == 'Linux' && matrix.target.cpu == 'i386'
         run: |
           sudo dpkg --add-architecture i386
-          sudo apt-fast update -qq
-          sudo DEBIAN_FRONTEND='noninteractive' apt-fast install \
+          sudo apt-get update -qq
+          sudo DEBIAN_FRONTEND='noninteractive' apt-get install \
             --no-install-recommends -yq gcc-multilib g++-multilib \
             libssl-dev:i386
           mkdir -p external/bin
@@ -167,13 +167,13 @@ jobs:
       # - name: Install library dependencies (Linux amd64)
       #   if: runner.os == 'Linux' && matrix.target.cpu == 'amd64'
       #   run: |
-      #     sudo DEBIAN_FRONTEND='noninteractive' apt-fast install \
+      #     sudo DEBIAN_FRONTEND='noninteractive' apt-get install \
       #       --no-install-recommends -yq libgmp-dev
       #
       # - name: Install library dependencies (Linux i386)
       #   if: runner.os == 'Linux' && matrix.target.cpu == 'i386'
       #   run: |
-      #     sudo DEBIAN_FRONTEND='noninteractive' apt-fast install \
+      #     sudo DEBIAN_FRONTEND='noninteractive' apt-get install \
       #       libgmp-dev:i386
       #
       # - name: Install library dependencies (macOS)