diff --git a/setup/generic/install.sh b/setup/generic/install.sh
index 08be974c..7a5f717c 100644
--- a/setup/generic/install.sh
+++ b/setup/generic/install.sh
@@ -40,7 +40,7 @@ rootdev="/dev/${rootname}"
 marker="/root/RESIZE_ATTEMPTED"
 
 # Check that the root partition is the last one.
-lastpart=$(sfdisk -l "$rootdev" | tail -1 | awk '{print $1}')
+lastpart=$(sfdisk -q -l "$rootdev" | tail +2 | sort -n -k 2 | tail -1 | awk '{print $1}')
 
 # Check if there is sufficient unpartitioned space after the last
 # partition to create the backingfiles and mutable partitions.
@@ -64,7 +64,7 @@ then
   devsectorsize=$(cat "/sys/block/${rootname}/queue/hw_sector_size")
   read -r fsblockcount fsblocksize < <(tune2fs -l "${rootpart}" | grep "Block count:\|Block size:" | awk ' {print $2}' FS=: | tr -d ' ' | tr '\n' ' ' | (cat; echo))
   fsnumsectors=$((fsblockcount * fsblocksize / devsectorsize))
-  partnumsectors=$(sfdisk -l -o Sectors "${rootdev}" | tail -1)
+  partnumsectors=$(sfdisk -q -l -o Sectors "${rootdev}" | tail +2 | sort -n | tail -1)
   partnumsectors=$((partnumsectors - 1));
   if [ "$partnumsectors" -le "$fsnumsectors" ]
   then
@@ -122,7 +122,7 @@ then
   # shrink root partition to match root file system size
   echo "shrinking root partition to match root fs, $fsnumsectors sectors"
   sleep 3
-  rootpartstartsector=$(sfdisk -l -o Start "${rootdev}" | tail -1)
+  rootpartstartsector=$(sfdisk -q -l -o Start "${rootdev}" | tail +2 | sort -n | tail -1)
   partnum=${rootpart:0-1}
 
   echo "${rootpartstartsector},${fsnumsectors}" | sfdisk --force "${rootdev}" -N "${partnum}"
diff --git a/setup/pi/create-backingfiles-partition.sh b/setup/pi/create-backingfiles-partition.sh
index d22855af..5df11167 100755
--- a/setup/pi/create-backingfiles-partition.sh
+++ b/setup/pi/create-backingfiles-partition.sh
@@ -82,7 +82,7 @@ else
   echo "DATA_DRIVE not set. Proceeding to SD card setup"
 fi
 
-readonly LAST_PARTITION_DEVICE=$(sfdisk -l "$BOOT_DISK" | tail -1 | awk '{print $1}')
+readonly LAST_PARTITION_DEVICE=$(sfdisk -q -l "$BOOT_DISK" | tail -1 | awk '{print $1}')
 readonly LAST_PART_NUM=${LAST_PARTITION_DEVICE:0-1}
 readonly SECOND_TO_LAST_PART_NUM=$((LAST_PART_NUM - 1))
 readonly SECOND_TO_LAST_PARTITION_DEVICE=${LAST_PARTITION_DEVICE:0:-1}${SECOND_TO_LAST_PART_NUM}
@@ -159,13 +159,10 @@ LAST_DISK_SECTOR=$((DISK_SECTORS - 1))
 # mutable partition is 100MB at the end of the disk, calculate its start sector
 FIRST_MUTABLE_SECTOR=$((LAST_DISK_SECTOR-204800+1))
 # backingfiles partition sits between the last and mutable partition, calculate its start sector and size
-LAST_PART_SECTOR=$(sfdisk -l "${BOOT_DISK}" | grep "${LAST_PARTITION_DEVICE}" | awk '{print $3}')
+LAST_PART_SECTOR=$(sfdisk -q -l "${BOOT_DISK}" | tail +2 | sort -n -k 2 | tail -1 | awk '{print $3}')
 FIRST_BACKINGFILES_SECTOR=$((LAST_PART_SECTOR + 1))
 BACKINGFILES_NUM_SECTORS=$((FIRST_MUTABLE_SECTOR - FIRST_BACKINGFILES_SECTOR))
 
-echo firstbackingfilesmutable $FIRST_BACKINGFILES_SECTOR
-echo first mutable $FIRST_MUTABLE_SECTOR
-
 # As a rule of thumb, one gigabyte of /backingfiles space can hold about 36
 # recording files. We need enough inodes in /mutable to create symlinks to
 # the recordings. Leaving enough headroom to account for short recordings,
diff --git a/tests/create-backingfiles-partition-test.sh b/tests/create-backingfiles-partition-test.sh
index 457c929c..4784c75a 100755
--- a/tests/create-backingfiles-partition-test.sh
+++ b/tests/create-backingfiles-partition-test.sh
@@ -130,9 +130,40 @@ EOF
   echo "BOOT_DISK: $BOOT_DISK"
 }
 
+# image with gpt partition layout and three partitions
+# on it already, but with the on-disk order not matching
+# the partition table order.
+function makeubuntulikeimage {
+  local img="$1"
+  truncate -s $((64*1024*1024*1024)) "$img"
+
+  sfdisk -X gpt "$img" << EOF
+2560M,3G
+12M,500M
+512M,2G
+EOF
+
+  fdisk -l "$img"
+
+  LOOP=$(sudo losetup --find --partscan --show "$img")
+
+  mkfs.ext4 "${LOOP}p1" &>> "$LOG"
+  mkfs.vfat "${LOOP}p2" &>> "$LOG"
+  mkfs.ext4 "${LOOP}p3" &>> "$LOG"
+
+  export BOOT_DISK="$LOOP"
+  export DATA_DRIVE=""
+  export CMDLINE_PATH="/dev/null"
+  export BOOT_DEVICE_PARTITION_PREFIX="${LOOP}p"
+
+  echo "BOOT_DISK: $BOOT_DISK"
+}
+
+
 SUCCESS=true
 
 function checksuccess {
+  printf 'Starting "%s"\n' "$1"
   cp /etc/fstab /etc/fstab.org
   if ../setup/pi/create-backingfiles-partition.sh /backingfiles /mutable && checknewpartitions
   then
@@ -147,6 +178,7 @@ function checksuccess {
 }
 
 function checkfailure {
+  printf 'Starting "%s"\n' "$1"
   if ! ../setup/pi/create-backingfiles-partition.sh
   then
     printf '%-45s %s\n' "$1" OK
@@ -217,6 +249,11 @@ checkenv
   checksuccess "one partition repeat"
   deleteimage
 
+  makeubuntulikeimage "$ROOT_IMAGE"
+  checksuccess "out of order partitions"
+  checksuccess "out of order partitions repeat"
+  deleteimage
+
   maketriplepartdosimage "$ROOT_IMAGE"
   checkfailure "three partitions dos"
   checkfailure "three partitions dos repeat"