diff -Nru livecd-rootfs-2.525.27/debian/changelog livecd-rootfs-2.525.28/debian/changelog
--- livecd-rootfs-2.525.27/debian/changelog	2019-06-10 17:46:16.000000000 +0000
+++ livecd-rootfs-2.525.28/debian/changelog	2019-07-16 12:20:18.000000000 +0000
@@ -1,3 +1,19 @@
+livecd-rootfs (2.525.28) bionic; urgency=medium
+
+  [ Tobias Koch ]
+  * Do proper error checking when calling snap-tool info to determine
+    the base of a snap. (LP: #1828500)
+
+  [ Michael Vogt ]
+  * Run "snap debug validate-seed" during preseeding to do basic validation of
+    the generated seed.yaml
+
+  [ Iain Lane ]
+  * Seed core for non minimized builds, as it is still required (LP:
+    #1836594).
+
+ -- Iain Lane <iain.lane@canonical.com>  Tue, 16 Jul 2019 13:20:18 +0100
+
 livecd-rootfs (2.525.27) bionic; urgency=medium
 
   * Backport improvements to snap seeding from trunk.  LP: #1831675.
diff -Nru livecd-rootfs-2.525.27/debian/control livecd-rootfs-2.525.28/debian/control
--- livecd-rootfs-2.525.27/debian/control	2019-06-10 17:46:03.000000000 +0000
+++ livecd-rootfs-2.525.28/debian/control	2019-07-16 12:20:18.000000000 +0000
@@ -33,7 +33,7 @@
          python3-software-properties,
          qemu-utils,
          rsync,
-         snapd,
+         snapd (>= 2.39),
          squashfs-tools (>= 1:3.3-1),
          sudo,
          u-boot-tools [armhf arm64],
diff -Nru livecd-rootfs-2.525.27/live-build/functions livecd-rootfs-2.525.28/live-build/functions
--- livecd-rootfs-2.525.27/live-build/functions	2019-06-10 17:46:03.000000000 +0000
+++ livecd-rootfs-2.525.28/live-build/functions	2019-07-16 12:20:18.000000000 +0000
@@ -445,12 +445,20 @@
             ;;
         *)
             # Determine if and what core snap is needed
-            local core_snap=$(/usr/share/livecd-rootfs/snap-tool info \
+            local snap_info
+
+            snap_info=$(/usr/share/livecd-rootfs/snap-tool info \
                 --cohort-key="${COHORT_KEY:-}" \
-                --channel="$CHANNEL" "$SNAP_NAME" | \
-                grep '^base:' | awk '{print $2}'
+                --channel="$CHANNEL" "${SNAP_NAME}" \
             )
 
+            if [ $? -ne 0 ]; then
+                echo "Failed to retrieve base of $SNAP_NAME!"
+                exit 1
+            fi
+
+            local core_snap=$(echo "$snap_info" | grep '^base:' | awk '{print $2}')
+
             # If $core_snap is not the empty string then SNAP itself is not a core
             # snap and we must additionally seed the core snap.
             if [ -n "$core_snap" ]; then
@@ -550,6 +558,12 @@
     local snaps_dir="$seed_dir/snaps"
 
     snap_prepare_assertions "$CHROOT_ROOT" "$CUSTOM_BRAND_MODEL"
+
+    # ubuntu-cpc:minimized has its own special snap handling
+    if [ "$PROJECT:${SUBPROJECT:-}" != ubuntu-cpc:minimized ]; then
+        # Download the core snap
+        _snap_preseed "$CHROOT_ROOT" core stable
+    fi
 }
 
 snap_preseed() {
@@ -571,6 +585,15 @@
             touch "$CHROOT_ROOT/var/lib/snapd/seed/.snapd-explicit-install-stamp"
             ;;
     esac
+
+
+    # Do basic validation of generated snapd seed.yaml, doing it here
+    # means we catch all the places(tm) that snaps are added but the
+    # downside is that each time a snap is added the seed must be valid,
+    # i.e. snaps with bases need to add bases first etc.
+    if [ -e chroot/var/lib/snapd/seed/seed.yaml ]; then
+        snap debug validate-seed "$CHROOT_ROOT/var/lib/snapd/seed/seed.yaml"
+    fi
 }
 
 is_live_layer () {