diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 82d765f..0ba46c0 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -96,8 +96,8 @@ jobs:
     - name: Test qemu_x86_virt + ${{ matrix.suite }} ${{ matrix.arch }}
       timeout-minutes: 15
       run: |
-        ./test/qemu.sh $RUNNER_TEMP/boot-qemu_x86_virt.bin.gz \
-                       $RUNNER_TEMP/${{ matrix.os }}-${{ matrix.suite }}-${{ matrix.arch }}-*.bin.gz
+        sudo ./test/qemu.sh $RUNNER_TEMP/boot-qemu_x86_virt.bin.gz \
+                            $RUNNER_TEMP/${{ matrix.os }}-${{ matrix.suite }}-${{ matrix.arch }}-*.bin.gz
 
   build-docker:
     runs-on: ubuntu-latest
diff --git a/scripts/build-debian b/scripts/build-debian
index a673940..563a5a8 100755
--- a/scripts/build-debian
+++ b/scripts/build-debian
@@ -181,10 +181,10 @@ ln -sf /run/systemd/resolve/stub-resolv.conf debian/etc/resolv.conf
 find debian ! -type d -printf "/%P\n" | sort > files.txt
 
 # Make a ext4 filesystem of this and put it into the image
-# >>> 3800000000 - (32 * 1024 * 1024)
-# 3766445568
+# >>> ((3800000000 - 32 * 1024 * 1024) // (1024 * 1024)) * (1024 * 1024)
+# 3765436416
 rm -f ext4.img
-fallocate -l 3766445568 ext4.img
+fallocate -l 3765436416 ext4.img
 mkfs.ext4 -d debian ext4.img
 pigz ext4.img
 
diff --git a/scripts/build-image b/scripts/build-image
index ee4f074..4eb8c22 100755
--- a/scripts/build-image
+++ b/scripts/build-image
@@ -12,7 +12,7 @@ rm -f "${IMAGE}"
 fallocate -v -l 3800000000 "${IMAGE}" # 3,800,000,000 bytes
 
 parted -s "${IMAGE}" mklabel msdos
-parted -s "${IMAGE}" mkpart primary fat32 -- 4MiB 32MiB # 28 MiB (50,331,648 bytes)
+parted -s "${IMAGE}" mkpart primary fat32 -- 4MiB 32MiB # 28 MiB (29,360,128 bytes)
 parted -s "${IMAGE}" mkpart primary ext2 -- 32MiB -1
 parted -s "${IMAGE}" set 2 boot on
 
diff --git a/test/qemu.sh b/test/qemu.sh
index 5f77d6a..4f851dd 100755
--- a/test/qemu.sh
+++ b/test/qemu.sh
@@ -20,12 +20,31 @@ echo "Using password ${SSHPASS}"
 # Build image
 zcat "${BOOT}" "${DEBIAN}" > image.bin
 
+# Check integrity
+LOOP1=$(losetup -f -P --show image.bin) && {
+    trap 'losetup -d "${LOOP1}"' ERR
+    fsck.vfat -p -f "${LOOP1}p1"
+    fsck.ext4 -p -f "${LOOP1}p2"
+    trap '-' ERR
+    losetup -d "${LOOP1}"
+}
+
 # Assume 8GB virtual disk
 fallocate -l 8GB image.bin
 
 # Extend second partition
 parted -s -a opt image.bin "resizepart 2 100%"
 
+# Check integrity again
+LOOP2=$(losetup -f -P --show image.bin) && {
+    trap 'losetup -d "${LOOP2}"' ERR
+    fsck.vfat -p -f "${LOOP2}p1"
+    fsck.ext4 -p -f "${LOOP2}p2"
+    resize2fs "${LOOP2}p2"
+    trap '-' ERR
+    losetup -d "${LOOP2}"
+}
+
 # Extract U-Boot (u-boot.rom in x86 case)
 dd if=image.bin of=bios.bin count=2048 skip=16