diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..1377554
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1 @@
+*.swp
diff --git a/firmware/critical/pieeprom-2019-09-10.bin b/firmware/critical/pieeprom-2019-09-10.bin
new file mode 100644
index 0000000..df5ead0
Binary files /dev/null and b/firmware/critical/pieeprom-2019-09-10.bin differ
diff --git a/firmware/recovery.bin b/firmware/recovery.bin
index 218375c..50717cd 100644
Binary files a/firmware/recovery.bin and b/firmware/recovery.bin differ
diff --git a/firmware/release-notes.md b/firmware/release-notes.md
index f0695e2..217e33b 100644
--- a/firmware/release-notes.md
+++ b/firmware/release-notes.md
@@ -1,6 +1,6 @@
 # Raspberry Pi4 bootloader EEPROM release notes
 
-## 2019-09-10 - Git f626c772 - (BETA)
+## 2019-09-10 - Git f626c772
    * Configure ethernet RGMII pins at power on. This is a minor change which
      which may improve reliability of ethernet for some users.
 
diff --git a/rpi-eeprom-config b/rpi-eeprom-config
index 32cbd80..ee39da2 100755
--- a/rpi-eeprom-config
+++ b/rpi-eeprom-config
@@ -15,7 +15,8 @@ IMAGE_SIZE = 512 * 1024
 # The number, order and size of the sections depends on the bootloader version
 # but the following mask can be used to test for section headers and skip
 # unknown data.
-MAGIC_MASK = 0x55aaf00f
+MAGIC = 0x55aaf00f
+MAGIC_MASK = 0xfffff00f
 FILE_MAGIC = 0x55aaf11f # id for modifiable file, currently only bootconf.txt
 FILE_HDR_LEN = 20
 FILENAME_LEN = 12
@@ -37,7 +38,7 @@ class BootloaderImage(object):
         magic = 0
         while offset < IMAGE_SIZE:
             magic, length = struct.unpack_from('>LL', self._bytes, offset)
-            if (magic & MAGIC_MASK) != MAGIC_MASK:
+            if (magic & MAGIC_MASK) != MAGIC:
                 raise Exception('EEPROM is corrupted')
 
             if magic == FILE_MAGIC: # Found a file
diff --git a/rpi-eeprom-update b/rpi-eeprom-update
index 1c3dc09..76a261f 100755
--- a/rpi-eeprom-update
+++ b/rpi-eeprom-update
@@ -167,16 +167,16 @@ getCurrentVersion() {
    fi
 }
 
-# Set to the latest critical firmware version
-CRITICAL_UPDATE_IMAGE=""
-CRITICAL_UPDATE_VERSION=0
-getLatestCriticalUpdate() {
-   CRITICAL_UPDATE_VERSION=0
+# Find latest applicable update version
+UPDATE_IMAGE=""
+UPDATE_VERSION=0
+getUpdateVersion() {
+   UPDATE_VERSION=0
    match=".*/pieeprom-[0-9][0-9][0-9][0-9]-[0-9][0-9]-[0-9][0-9].bin"
    latest="$(find "${FIRMWARE_IMAGE_DIR}" -maxdepth 1 -type f -size "${EEPROM_SIZE}c" -regex "${match}" | sort -r | head -n1)"
    if [ -f "${latest}" ]; then
-      CRITICAL_UPDATE_VERSION=$(strings "${latest}" | grep BUILD_TIMESTAMP | sed 's/.*=//g')
-      CRITICAL_UPDATE_IMAGE="${latest}"
+      UPDATE_VERSION=$(strings "${latest}" | grep BUILD_TIMESTAMP | sed 's/.*=//g')
+      UPDATE_IMAGE="${latest}"
    fi
 }
 
@@ -189,11 +189,11 @@ checkDependencies() {
    fi
 
    if [ ! -d "${FIRMWARE_IMAGE_DIR}" ]; then
-      die "Bootloader critical updates directory ${FIRMWARE_IMAGE_DIR} not found."
+      die "Bootloader updates directory ${FIRMWARE_IMAGE_DIR} not found."
    fi
 
    if vcgencmd bootloader_config | grep -qi "Command not registered"; then
-      die "vcgencmd: bootloader_config. not supported. Please update VC firmware"
+      die "vcgencmd: 'bootloader_config' command not supported. Please update VC firmware"
    fi
 
    if ! flashrom --version > /dev/null 2>&1; then
@@ -201,14 +201,14 @@ checkDependencies() {
    fi
 
    if [ "${USE_FLASHROM}" = 0 ]; then
-      [ -f "${RECOVERY_BIN}" ] || die "${RECOVERY_BIN} not found"
+      [ -f "${RECOVERY_BIN}" ] || die "${RECOVERY_BIN} not found."
    fi
 }
 
 usage() {
 cat <<EOF
 rpi-eeprom-update [options]... [FILE]
-   Checks whether there Raspberry Pi bootloader EEPROM is up to date and
+   Checks whether the Raspberry Pi bootloader EEPROM is up-to-date and
    optionally updates the EEPROM at the next reboot.
 
    The default update mechanism writes recovery.bin and pieeprom.upd to the
@@ -230,9 +230,9 @@ rpi-eeprom-update [options]... [FILE]
    A backup of the current EEPROM config file is written to ${FIRMWARE_BACKUP_DIR}
    before applying the update.
 
-   -a Install the latest critical update if necessary.
-   -d Use the default bootloader config instead of migrating the current settings.
-   -f Install the given file instead of the latest critical update.
+   -a Install the latest update if necessary
+   -d Use the default bootloader config instead of migrating the current settings
+   -f Install the given file instead of the latest applicable update
       Ignores the FREEZE_VERSION flag in bootloader and is intended for manual
       firmware updates.
       WARNING: This command should only be run from console mode in order to
@@ -241,19 +241,20 @@ rpi-eeprom-update [options]... [FILE]
    -j Write status information using JSON notation
    -m Write status information to the given file when run without -a or -f
 
-   To extract the configuration file from an EEPROM image.
+
+   To extract the configuration file from an EEPROM image: 
    rpi-eeprom-config pieeprom.bin --out bootconf.txt
 
-   To update the configuration file in an EEPROM image.
+   To update the configuration file in an EEPROM image: 
    rpi-eeprom-config pieeprom.bin --config bootconf.txt --out pieeprom-new.bin
 
-   To flash the new image
+   To flash the new image: 
    sudo rpi-eeprom-update -d -f ./pieeprom-new.bin
 
    The syntax is the same as config.txt but section filters etc are not supported. See
-   online documentation for the list of paramters.
+   online documentation for the list of parameters.
 
-   The official documentation for the Raspberry Pi bootloader EEPROM is available here:-
+   The official documentation for the Raspberry Pi bootloader EEPROM is available at
    https://www.raspberrypi.org/documentation/hardware/raspberrypi/booteeprom.md
 
 EOF
@@ -292,12 +293,12 @@ findBootFS()
 checkAndApply()
 {
    getCurrentVersion
-   getLatestCriticalUpdate
+   getUpdateVersion
 
-   if [ "${CRITICAL_UPDATE_VERSION}" -gt "${CURRENT_VERSION}" ]; then
-      printVersions "${CURRENT_VERSION}" "${CRITICAL_UPDATE_VERSION}"
+   if [ "${UPDATE_VERSION}" -gt "${CURRENT_VERSION}" ]; then
+      printVersions "${CURRENT_VERSION}" "${UPDATE_VERSION}"
       echo "*** INSTALLING REQUIRED UPDATE ***"
-      applyUpdate "${CRITICAL_UPDATE_IMAGE}"
+      applyUpdate "${UPDATE_IMAGE}"
       echo "Bootloader EEPROM update pending. Please reboot to apply the update."
    else
       echo "Bootloader EEPROM is up to date. $(date -d@${CURRENT_VERSION})"
@@ -330,16 +331,16 @@ removePreviousUpdates()
 checkVersion()
 {
    getCurrentVersion
-   getLatestCriticalUpdate
-   if [ "${CRITICAL_UPDATE_VERSION}" -gt "${CURRENT_VERSION}" ]; then
+   getUpdateVersion
+   if [ "${UPDATE_VERSION}" -gt "${CURRENT_VERSION}" ]; then
       echo "*** UPDATE REQUIRED ***"
-      printVersions "${CURRENT_VERSION}" "${CRITICAL_UPDATE_VERSION}"
-      write_status_info EXIT_UPDATE_REQUIRED "${CURRENT_VERSION}" "${CRITICAL_UPDATE_VERSION}"
+      printVersions "${CURRENT_VERSION}" "${UPDATE_VERSION}"
+      write_status_info EXIT_UPDATE_REQUIRED "${CURRENT_VERSION}" "${UPDATE_VERSION}"
       exit ${EXIT_UPDATE_REQUIRED}
    else
       echo "Bootloader EEPROM is up to date"
-      printVersions "${CURRENT_VERSION}" "${CRITICAL_UPDATE_VERSION}"
-      write_status_info EXIT_SUCCESS "${CURRENT_VERSION}" "${CRITICAL_UPDATE_VERSION}"
+      printVersions "${CURRENT_VERSION}" "${UPDATE_VERSION}"
+      write_status_info EXIT_SUCCESS "${CURRENT_VERSION}" "${UPDATE_VERSION}"
       exit ${EXIT_SUCCESS}
    fi
 }
diff --git a/test/bootconf-2019-05-10.txt b/test/bootconf-2019-05-10.txt
new file mode 100644
index 0000000..2f9f956
--- /dev/null
+++ b/test/bootconf-2019-05-10.txt
@@ -0,0 +1,2 @@
+BOOT_UART=0
+WAKE_ON_GPIO=0
diff --git a/test/bootconf-2019-07-15-freeze.txt b/test/bootconf-2019-07-15-freeze.txt
new file mode 100644
index 0000000..db43a54
--- /dev/null
+++ b/test/bootconf-2019-07-15-freeze.txt
@@ -0,0 +1,16 @@
+BOOT_UART=0
+WAKE_ON_GPIO=1
+POWER_OFF_ON_HALT=0
+FREEZE_VERSION=1                                                              
+                                                                              
+                                                                              
+                                                                              
+                                                                              
+                                                                              
+                                                                              
+                                                                              
+                                                                              
+                                                                              
+                                                                             
+                                                                              
+             
diff --git a/test/bootconf-2019-07-15.txt b/test/bootconf-2019-07-15.txt
new file mode 100644
index 0000000..8cf72d5
--- /dev/null
+++ b/test/bootconf-2019-07-15.txt
@@ -0,0 +1,16 @@
+BOOT_UART=0
+WAKE_ON_GPIO=1
+POWER_OFF_ON_HALT=0
+                                                                              
+                                                                              
+                                                                              
+                                                                              
+                                                                              
+                                                                              
+                                                                              
+                                                                              
+                                                                              
+                                                                              
+                                                                             
+                                                                              
+             
diff --git a/test/pieeprom-2019-07-15-freeze.bin b/test/pieeprom-2019-07-15-freeze.bin
new file mode 100644
index 0000000..cc791ee
Binary files /dev/null and b/test/pieeprom-2019-07-15-freeze.bin differ
diff --git a/test/test-rpi-eeprom-config b/test/test-rpi-eeprom-config
new file mode 100755
index 0000000..309b991
--- /dev/null
+++ b/test/test-rpi-eeprom-config
@@ -0,0 +1,75 @@
+#!/bin/sh
+
+set -e
+
+script_dir="$(cd "$(dirname "$0")" && pwd)"
+die() {
+   echo "$@" >&2
+   exit 1
+}
+
+TMP_CONFIG=""
+TMP_EEPROM=""
+cleanup() {
+   rm -f "${TMP_CONFIG}" -f "${TMP_EEPROM}"
+   TMP_CONFIG=""
+   TMP_EEPROM=""
+}
+trap cleanup EXIT
+
+check_loopback()
+{
+   echo "check_update $1 $2"
+
+   image="${script_dir}/$1"
+   conf="${script_dir}/$2"
+
+   # Check that the production config file can be read correctly
+   expected_md5="$(md5sum "${conf}" | awk '{print $1}')"
+   actual_md5="$("${script_dir}/../rpi-eeprom-config" "${image}" | md5sum | awk '{print $1}')"
+   [ "${actual_md5}" = "${expected_md5}" ] || die "Config-read: checksum mismatch"
+
+   # Check that overwriting the config section produces an identical binary
+   TMP_EEPROM=$(mktemp)
+   "${script_dir}/../rpi-eeprom-config" \
+      "${image}" \
+      --config "${conf}" \
+      --out "${TMP_EEPROM}"
+
+   expected_md5="$(md5sum "${image}" | awk '{print $1}')"
+   actual_md5="$(md5sum "${TMP_EEPROM}" | awk '{print $1}')"
+   [ "${actual_md5}" = "${expected_md5}" ] || die "EEPROM loopback: checksum mismatch"
+}
+
+# Update the EEPROM with a new config and check the expected image is produced
+check_update()
+{
+   echo "check_update $1 $2 $3"
+
+   image="${script_dir}/$1"
+   ref_image="${script_dir}/$2"
+   conf="${script_dir}/$3"
+
+   expected_md5="$(md5sum "${ref_image}" | awk '{print $1}')"
+
+   TMP_EEPROM="$(mktemp)"
+   "${script_dir}/../rpi-eeprom-config" \
+      "${image}" \
+      --config "${conf}" \
+      --out "${TMP_EEPROM}"
+
+   actual_md5="$(md5sum "${TMP_EEPROM}" | awk '{print $1}')"
+   if [ "${actual_md5}" != "${expected_md5}" ]; then
+      hexdump -C "${TMP_EEPROM}" > "tmp.hex"
+      die "EEPROM update: checksum mismatch"
+   fi
+}
+
+check_loopback "../firmware/critical/pieeprom-2019-05-10.bin" "bootconf-2019-05-10.txt"
+cleanup
+
+check_loopback "../firmware/critical/pieeprom-2019-07-15.bin" "bootconf-2019-07-15.txt"
+cleanup
+
+check_update "../firmware/critical/pieeprom-2019-07-15.bin" "pieeprom-2019-07-15-freeze.bin" "bootconf-2019-07-15-freeze.txt"
+cleanup