diff --git a/content/boards/chromebooks/01-debugging_interfaces.md b/content/boards/chromebooks/01-debugging_interfaces.md
index 29add922eeac8b1b005bd59581981c189e10f086..00e397c9e897ee36eae66f6b8122bb8fd28a060a 100644
--- a/content/boards/chromebooks/01-debugging_interfaces.md
+++ b/content/boards/chromebooks/01-debugging_interfaces.md
@@ -219,3 +219,97 @@ $ dut-control -p 9932 cold_reset:on
 
 If this worked as expected, congratulations!  Your Chromebook is now
 ready to be automated in the LAVA test lab.
+
+
+## Upgrading the Servo v4 firmware
+
+There are many versions of the Servo v4 firmware. It's recommended to
+upgrade it to a recent version whenever possible, as older versions have
+shown some issues with certain boards and
+[Depthcharge](../04-bootloader_setup) versions.
+
+You can check the current Servo v4 firmware version using the CLI that
+the Servo runs in the first serial terminal it enumerates
+(`/dev/ttyUSB0` in the example below, it could be different in your
+setup):
+
+```
+$ miniterm /dev/ttyUSB0
+
+> version
+Board:   3
+RO:      servo_v4_v2.3.22-ecb74cc56
+RW:      servo_v4_v2.3.22-ecb74cc56
+Build:   servo_v4_v2.3.22-ecb74cc56
+         2019-07-23 18:07:15 @chromeos-legacy-release-us-central2-c-x32-40-2efr
+```
+
+The `servo_updater` tool (installed from the
+[dependencies](#dependencies) above) can be used to flash the Servo v4
+firmware. To use it, first clone the [firmware-tools
+repo](https://gitlab.collabora.com/chromium/firmware-tools). Then make
+sure the Servo v4 is connected to your host and run:
+
+```
+$ cd firmware-tools
+$ sudo PATH=$PWD/bin:$PATH LD_LIBRARY_PATH=$PWD/lib servo_updater -f <firmware_file>
+```
+
+The `servo_v4_fw` directory in `firmware-tools` includes some tested
+Servo v4 firmware binaries. You can usually find these binaries in the
+ChromeOS SDK (`usr/share/servo_updater/firmware/` inside the cros-build
+chroot).
+
+If everything goes well you should see an output like this:
+
+```
+Current servo_v4 version is   servo_v4_v2.3.22-ecb74cc56
+Available servo_v4 version is servo_v4_v2.4.35-f1113c92b
+Updating to recommended version.
+usb_updater2 -d 18d1:501b -n servo_v4_fw/servo_v4_v2.4.35-f1113c92b.bin
+read 131072(0x20000) bytes from servo_v4_fw/servo_v4_v2.4.35-f1113c92b.bin
+Found device.
+found interface 4 endpoint 6, chunk_len 64
+READY
+-------
+start
+target running protocol version 6 (type 1)
+maximum PDU size: 1024
+Flash protection status: 0008
+version:       servo_v4_v2.3.22-ecb74cc56
+key_version: 0
+min_rollback: -1
+offset: writable at 0x10000
+sending 0xe760 bytes to 0x10000
+-------
+update complete
+image updated
+usb_updater2 -d 18d1:501b -n servo_v4_fw/servo_v4_v2.4.35-f1113c92b.bin
+read 131072(0x20000) bytes from servo_v4_fw/servo_v4_v2.4.35-f1113c92b.bin
+Found device.
+found interface 4 endpoint 6, chunk_len 64
+READY
+-------
+start
+target running protocol version 6 (type 1)
+maximum PDU size: 1024
+Flash protection status: 0008
+version:       servo_v4_v2.3.22-ecb74cc56
+key_version: 0
+min_rollback: -1
+offset: writable at 0
+sending 0xe8d4 bytes to 0
+-------
+update complete
+image updated
+```
+
+If you have more than one Servo v4 interface connected to the host, you
+can specify which one you want to flash using the `-s <serial_number>`
+option of `servo_updater`. The serial number of an interface can also be
+retrieved from its CLI using the `serialno` command:
+
+```
+> serialno
+Serial number: C1706310161
+```