diff --git a/docker-bake.hcl b/docker-bake.hcl
index af09d1d..971e096 100644
--- a/docker-bake.hcl
+++ b/docker-bake.hcl
@@ -35,6 +35,8 @@ target "base" {
   dockerfile-inline = <<EOF
 FROM --platform=linux/amd64 ubuntu:jammy as build-amd64
 FROM --platform=linux/arm64 nvcr.io/nvidia/l4t-base:r36.2.0 as build-arm64
+RUN sed -i.bak -r 's!http://ports.ubuntu.com/ubuntu-ports/!https://mirror.kumi.systems/ubuntu-ports/!' /etc/apt/sources.list && \
+    cat /etc/apt/sources.list
 FROM build-$TARGETARCH
 EOF
   platforms  = "${PLATFORMS}"
diff --git a/docker/humble-custom/Dockerfile b/docker/humble-custom/Dockerfile
index f579838..a6f2933 100644
--- a/docker/humble-custom/Dockerfile
+++ b/docker/humble-custom/Dockerfile
@@ -8,8 +8,6 @@ ARG TARGETARCH
 
 # downgrade libopencv-dev for ROS2
 RUN if [ "$TARGETARCH" = "arm64" ]; then \
-	sed -i.bak -r 's!http://ports.ubuntu.com/ubuntu-ports/!https://mirror.kumi.systems/ubuntu-ports/!' /etc/apt/sources.list && \
-	cat /etc/apt/sources.list && \
         apt update && apt install -q -y --no-install-recommends --allow-downgrades \
         libopencv-dev=4.5.4+dfsg-9ubuntu4 \
         && \