ci: Fetch grub-cc from Fedora Koji

Dockerfile

@@ -110,32 +110,8 @@ RUN --mount=type=tmpfs,target=/run --mount=type=tmpfs,target=/tmp <<EOF
     fi
 EOF
 
-# Get the latest GrubCC binary
-FROM quay.io/fedora/eln:latest AS grub-cc-download
-RUN --mount=type=tmpfs,target=/run --mount=type=tmpfs,target=/tmp <<EOF
-set -eux
-
-# There isn't a generic grub2-efi-cc package that DNF can automatically resolve
-case "$(uname -m)" in
-    x86_64)
-        dnf download grub2-efi-x64-cc
-        ;;
-    aarch64)
-        dnf download grub2-efi-aa64-cc
-        ;;
-    *)
-        echo "Unsupported architecture: $(uname -m)" >&2
-        exit 1
-        ;;
-esac
-
-mv ./*.rpm grub-cc.rpm
-
-EOF
-
 FROM scratch as fetch
 COPY --from=target-base /target-rootfs/ /
-COPY --from=grub-cc-download /grub-cc.rpm /var/grub-cc.rpm
 # SKIP_CONFIGS=1 skips LBIs, test kargs, and install configs (for FCOS testing)
 ARG SKIP_CONFIGS
 ARG boot_type
@@ -172,6 +148,24 @@ RUN --mount=type=tmpfs,target=/run --mount=type=tmpfs,target=/tmp \
         dnf install -y "${pkgs_to_install[@]}"
     fi
 
+    if [[ "$bootloader" == "grub-cc" ]]; then
+        case "$(uname -m)" in
+            x86_64)
+                grub_cc_url=https://kojipkgs.fedoraproject.org/packages/grub2/2.12/60.eln156/x86_64/grub2-efi-x64-cc-2.12-60.eln156.x86_64.rpm
+                ;;
+            aarch64)
+                grub_cc_url=https://kojipkgs.fedoraproject.org/packages/grub2/2.12/60.eln156/aarch64/grub2-efi-aa64-cc-2.12-60.eln156.aarch64.rpm
+                ;;
+            *)
+                echo "Unsupported architecture: $(uname -m)" >&2
+                exit 1
+                ;;
+        esac
+
+        curl --fail --location --retry 5 --retry-all-errors --retry-delay 1 \
+            --output /var/grub-cc.rpm "$grub_cc_url"
+    fi
+
     # Currently dnf installs grub-cc at /usr/lib/efi/grub2/1:2.12-60.eln156/EFI/eln/cc/grubx64-cc.efi
     # which is less than ideal because: 
     # - the "cc" subdirectory
@@ -181,7 +175,8 @@ RUN --mount=type=tmpfs,target=/run --mount=type=tmpfs,target=/tmp \
     # we can copy the EFI binary to the ESP
     if [[ "$bootloader" == "grub-cc" ]]; then
         mkdir /var/grub-cc
-        rpm2archive /var/grub-cc.rpm | tar -xvz -C /var/grub-cc
+        rpm2archive /var/grub-cc.rpm > /tmp/grub-cc.tar.gz
+        tar -xvz -f /tmp/grub-cc.tar.gz -C /var/grub-cc
         file=$(find /var/grub-cc -name '*.efi')
         mkdir -p /usr/lib/grub-cc
         cp "$file" /usr/lib/grub-cc/grub-cc.efi