diff --git a/meta-isar/conf/distro/ubuntu-common.inc b/meta-isar/conf/distro/ubuntu-common.inc
index 232bee35..2c2f02f8 100644
--- a/meta-isar/conf/distro/ubuntu-common.inc
+++ b/meta-isar/conf/distro/ubuntu-common.inc
@@ -37,4 +37,5 @@ SYSTEMD_BOOTLOADER_INSTALL:focal = "systemd:${DISTRO_ARCH}"
 SYSTEMD_BOOTLOADER_INSTALL:jammy = "systemd:${DISTRO_ARCH}"
 
 # snapshot mirror for reproducible builds
-DISTRO_APT_SNAPSHOT_PREMIRROR ??= "(http|https)://archive.ubuntu.com/(.*) https://snapshot.ubuntu.com/\2/${APT_SNAPSHOT_DATE}/\n"
+DISTRO_APT_SNAPSHOT_PREMIRROR_BASE ??= "snapshot.ubuntu.com"
+DISTRO_APT_SNAPSHOT_PREMIRROR ??= "(http|https)://archive.ubuntu.com/(.*) https://${DISTRO_APT_SNAPSHOT_PREMIRROR_BASE}/\2/${APT_SNAPSHOT_DATE}/\n"
diff --git a/meta/conf/distro/debian-common.conf b/meta/conf/distro/debian-common.conf
index 8c6a3f63..de9e6933 100644
--- a/meta/conf/distro/debian-common.conf
+++ b/meta/conf/distro/debian-common.conf
@@ -40,4 +40,5 @@ COMPAT_DISTRO_ARCH:amd64 = "i386"
 COMPAT_DISTRO_ARCH:arm64 = "armhf"
 
 # snapshot mirror for reproducible builds
-DISTRO_APT_SNAPSHOT_PREMIRROR ??= "deb.debian.org/(.*) snapshot.debian.org/archive/\1/${APT_SNAPSHOT_DATE}/\n"
+DISTRO_APT_SNAPSHOT_PREMIRROR_BASE ??= "snapshot.debian.org"
+DISTRO_APT_SNAPSHOT_PREMIRROR ??= "deb.debian.org/(.*) ${DISTRO_APT_SNAPSHOT_PREMIRROR_BASE}/archive/\1/${APT_SNAPSHOT_DATE}/\n"