diff --git a/sdk_container/src/third_party/coreos-overlay/app-admin/google-guest-agent/google-guest-agent-20240314.00.ebuild b/sdk_container/src/third_party/coreos-overlay/app-admin/google-guest-agent/google-guest-agent-20240314.00.ebuild
index 03f8c986f7..1925de583b 100644
--- a/sdk_container/src/third_party/coreos-overlay/app-admin/google-guest-agent/google-guest-agent-20240314.00.ebuild
+++ b/sdk_container/src/third_party/coreos-overlay/app-admin/google-guest-agent/google-guest-agent-20240314.00.ebuild
@@ -20,7 +20,8 @@ DESCRIPTION="Google Guest Agent"
 HOMEPAGE="https://github.com/GoogleCloudPlatform/guest-agent"
 
 SRC_URI="https://github.com/GoogleCloudPlatform/guest-agent/archive/${PV}.tar.gz -> ${P}.tar.gz"
-SRC_URI+=" ${P}-deps.tar.xz"
+# Flatcar: explicitly reference mirror
+SRC_URI+=" https://commondatastorage.googleapis.com/cos-localmirror/distfiles/${P}-deps.tar.xz"
 
 LICENSE="Apache-2.0 BSD ZLIB"
 SLOT="0"
diff --git a/sdk_container/src/third_party/coreos-overlay/app-admin/google-osconfig-agent/google-osconfig-agent-20240320.00.ebuild b/sdk_container/src/third_party/coreos-overlay/app-admin/google-osconfig-agent/google-osconfig-agent-20240320.00.ebuild
index d8dfdd2d1c..1d0bcf1045 100644
--- a/sdk_container/src/third_party/coreos-overlay/app-admin/google-osconfig-agent/google-osconfig-agent-20240320.00.ebuild
+++ b/sdk_container/src/third_party/coreos-overlay/app-admin/google-osconfig-agent/google-osconfig-agent-20240320.00.ebuild
@@ -21,7 +21,8 @@ DESCRIPTION="Google OS Config Agent"
 HOMEPAGE="https://github.com/GoogleCloudPlatform/osconfig"
 
 SRC_URI="https://github.com/GoogleCloudPlatform/osconfig/archive/${PV}.tar.gz -> ${P}.tar.gz"
-SRC_URI+=" ${P}-deps.tar.xz"
+# Flatcar: explicitly reference mirror
+SRC_URI+=" https://commondatastorage.googleapis.com/cos-localmirror/distfiles/${P}-deps.tar.xz"
 
 LICENSE="Apache-2.0 BSD"
 SLOT="0"