diff --git a/.github/workflows/container-mirror-images.json b/.github/workflows/container-mirror-images.json
index 22e9f782108..7bca6e6ad9d 100644
--- a/.github/workflows/container-mirror-images.json
+++ b/.github/workflows/container-mirror-images.json
@@ -3,7 +3,7 @@
     {
       "image": "library/ubuntu",
       "repo": "docker.io",
-      "sha256": "965fbcae990b0467ed5657caceaec165018ef44a4d2d46c7cdea80a9dff0d1ea"
+      "sha256": "5d070ad5f7fe63623cbb99b4fc0fd997f5591303d4b03ccce50f403957d0ddc4"
     },
     {
       "image": "ryantk/minica",
diff --git a/MODULE.bazel b/MODULE.bazel
index 191099c6403..234e75252c6 100644
--- a/MODULE.bazel
+++ b/MODULE.bazel
@@ -194,14 +194,6 @@ oci.pull(
 )
 use_repo(oci, "rust_base", "rust_base_linux_amd64")
 
-# used in various places as base
-oci.pull(
-    name = "ubuntu_base",
-    image = "ghcr.io/dfinity/ubuntu@sha256:965fbcae990b0467ed5657caceaec165018ef44a4d2d46c7cdea80a9dff0d1ea",
-    platforms = ["linux/amd64"],
-)
-use_repo(oci, "ubuntu_base", "ubuntu_base_linux_amd64")
-
 # used by boundary node tests
 oci.pull(
     name = "coredns",
diff --git a/ic-os/bootloader/build-bootloader-tree.sh b/ic-os/bootloader/build-bootloader-tree.sh
index 34f95386343..465b4d5e419 100755
--- a/ic-os/bootloader/build-bootloader-tree.sh
+++ b/ic-os/bootloader/build-bootloader-tree.sh
@@ -25,11 +25,12 @@ sudo mount -t tmpfs tmpfs-podman "${TMPFS}"
 trap 'rm -rf "${TMPDIR}"; sudo podman --root "${TMPFS}" rm -f "${CONTAINER}"' exit
 TMPDIR=$(mktemp -d -t build-image-XXXXXXXXXXXX)
 
-BASE_IMAGE="docker.io/dfinity/ic-build-bazel@sha256:1978886cfda51b09057bffd60f2e5edb588c6c0b74de87696cd4e964335dba87"
+BASE_IMAGE="ghcr.io/dfinity/library/ubuntu@sha256:5d070ad5f7fe63623cbb99b4fc0fd997f5591303d4b03ccce50f403957d0ddc4"
 
 sudo podman --root "${TMPFS}" build --iidfile ${TMPDIR}/iidfile - <<<"
     FROM $BASE_IMAGE
     USER root:root
+    RUN apt-get -y update && apt-get -y --no-install-recommends install grub-efi faketime
     RUN mkdir -p /build/boot/grub
     RUN cp -r /usr/lib/grub/x86_64-efi /build/boot/grub
     RUN mkdir -p /build/boot/efi/EFI/Boot
diff --git a/ic-os/bootloader/grub.cfg b/ic-os/bootloader/grub.cfg
index 3e08ce4794c..91caceb75ba 100644
--- a/ic-os/bootloader/grub.cfg
+++ b/ic-os/bootloader/grub.cfg
@@ -1,4 +1,4 @@
-regexp -s boot_disk '^\(([a-z0-9]*),[a-z0-9]*\)/EFI/BOOT' $cmdpath
+regexp -s boot_disk '^\(([a-z0-9]*),[a-z0-9]*\)/EFI/BOOT' $fw_path
 
 set prefix=($boot_disk,gpt2)