Cisco Meraki MR42

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abgn+ac (AC1900)
Wireless Access Point
Wikipedia Cisco Systems
3rd Party Firmware
dd-wrt Status Unknown
OpenWrt Supported
Tomato any flavor Incompatible
Gargoyle Status Unknown
Platform
BrandModelRev Cisco Meraki MR42
FCC ID (fcc.io) UDX-60063010
FCC ID (fcc.report) UDX-60063010
Type access point
CPU1 Question? Qualcomm Atheros IPQ8068
CPU1 Type ARMv7 Cortex-A15
CPU1 Speed 1.4 GHz ( 2 cores )
Flash1 Chip Brand? Model?
Flash1 Size 128 MiB 134,217,728 B <br />1,048,576 Kib <br />131,072 KiB <br />1,024 Mib <br />0.125 GiB <br /> (NAND)
RAM1 Size 512 MiB 536,870,912 B <br />4,194,304 Kib <br />524,288 KiB <br />4,096 Mib <br />0.5 GiB <br />
RAM1 Chip Brand? Model?
ETH chip1 Qualcomm Atheros IPQ8068
ETH chip2 Atheros AR8033
Ethernet Port Count 1-1GbE-LAN
Wired Standard IEEE 802.3i/3u/3ab

802dot11 OUI: none specified

Stock bootloader U-Boot
Expansion IF types none specified
PoE 802.3at, 802.3af, standard
Power 12 VDC, ? A
Serial Port (UART) yes, 3.3V TTL, (115200 8N1)
JTAG Port yes
Other
3rd Party Firmware Support OpenWrt • (List | Dev | DLs)
Retail
Availability End of Life
End of Life date 2021
(Est.) release date 15 February 2016
ASIN B01BSZEQIM
Physical
Dimensions 9.98 x 6.13 x 1.46 inches
Weight 1.54 pounds
Radio 1
Chip1 Qualcomm Atheros QCA9992
Wireless interface OUI none specified
Antenna Connector Type none specified
MIMO status 3x3:3
Wireless Standard IEEE 802.11b/g/n
N-QAM up to 600 Mbps
802.11n up to 450 Mbps
802.11g up to 54 Mbps
802.11b up to 11 Mbps
WiFi Operating Frequency 2.4 GHz
Radio 2
Chip1 Qualcomm Atheros QCA9992
Wireless interface OUI none specified
Antenna Connector Type none specified
MIMO status 3x3:3
Wireless Standard IEEE 802.11a/n/ac
802.11ac up to 1300 Mbps
802.11n up to 450 Mbps
802.11a up to 54 Mbps
WiFi Operating Frequency 5 GHz
Radio 3
Chip1 Qualcomm Atheros QCA9889
Wireless interface OUI none specified
Antenna Connector Type none specified
MIMO status 1x1:1
Wireless Standard IEEE 802.11a/b/g/n/ac
WiFi Operating Frequency 2.4 or 5 GHz
Radio 4
Chip1 Brand? Model?
Wireless interface OUI none specified
Antenna Connector Type none specified
Wireless Standard Bluetooth
WiFi Operating Frequency 2.4 GHz

For a list of all currently documented Atheros (QCA) chipsets with specifications, see Atheros.
For a list of all currently documented Qualcomm Atheros (QCA) chipsets with specifications, see Qualcomm Atheros.

For a list of all currently documented Cisco devices with specifications, see Cisco.

600 Mbps - 3SS 2.4GHz 802.11n (40MHz chan., 256-QAM),
1300 Mbps - 3SS 5GHz 802.11ac (80MHz chan.) = AC1900 class

Overview

Datasheet

Radios • >>
2.4 GHz 802.11b/g/n client access radio
5 GHz 802.11a/n/ac client access radio
2.4 GHz & 5 GHz dual-band WIDS/WIPS, spectrum
analysis, & location analytics radio
2.4 GHz Bluetooth radio with Bluetooth Low Energy
(BLE) and Beacon support
Concurrent operation of all four radios
Max aggregate frame rate 1.9 Gbit/s
Supported frequency bands (country-specific restric-
tions apply):
2.412-2.484 GHz
5.150-5.250 GHz (UNII-1)
5.250-5.350 GHZ (UNII-2)
5.470-5.600, 5.660-5.725 GHz (UNII-2e)
5.725 -5.825 GHz (UNII-3)

Flashing

Flashing OpenWrt

Target: ipq806x
Subtarget: generic
Package architecture: arm_cortex-a15_neon-vfpv4
Supported Since Commit
Support started version: 22.03.0
Current supported version: 24.10.4
WLAN Hardware: Qualcomm Atheros QCA9992, Qualcomm Atheros QCA9889
Installation method(s):
see git-commit

(MR42 Only) Installation via diagnostic mode:

If you can successfully complete step 1 then you can continue to install
via this method without having to open the device. Otherwise please use
the standard UART method. Please note that when booting via TFTP, some
Ethernet devices, in particular those on laptops, will not connect in
time, resulting in TFTP boot not succeeding. In this instance it is
advised to connect via a switch.
 1. Hold down reset at power on and keep holding, after around 10 seconds
    if the orange LED changes behaviour to begin flashing, proceed to
    release reset, then press reset two times. Ensure that the LED has
    turned blue. Note that flashing will occur on some devices, but it
    will not be possible to change the LED colour using the reset button.
    In this case it will still be possible to continue with this install
    method.
 2. Set your IP to 192.168.1.250. Set up a TFTP server serving
    mr42_u-boot.mbn and
    openwrt-ipq806x-generic-meraki_mr42-initramfs-fit-uImage.itb, obtained
    from [1].
 3. Use telnet and connect to 192.168.1.1. Run the following commands to
    install u-boot. Note that all these commands are critical, an error
    will likely render the device unusable.
    Option 3.1:
      If you are sure you have set up the TFTP server correctly you can
      run this script on the device. This will download and flash the
      u-boot image immediately:
      `/etc/update_uboot.sh 192.168.1.250 mr42_u-boot.mbn`
      Once completed successfully, power off the device.
    Option 3.2:
      If you are unsure the TFTP server is correctly set up you can
      obtain the image and flash manually:
      3.2.1. `cd /tmp`
      3.2.2. `tftp-hpa 192.168.1.250 -m binary -c get mr42_u-boot.mbn`
      3.2.3. Confirm file has downloaded correctly by comparing the
             md5sum:
           `md5sum mr42_u-boot.mbn`
      3.2.4. The following are the required commands to write the image.
           `echo 1 > /sys/devices/platform/msm_nand/boot_layout
            mtd erase /dev/mtd1
            nandwrite -pam /dev/mtd1 mr42_u-boot.mbn
            echo 0 > /sys/devices/platform/msm_nand/boot_layout`
         Important: You must observe the output of the `nandwrite`
         command. Look for the following to verify writing is occurring:
           `Writing data to block 0 at offset 0x0
            Writing data to block 1 at offset 0x20000
            Writing data to block 2 at offset 0x40000`
         If you do not see this then do not power off the device. Check
         your previous commands and that mr42_u-boot.mbn was downloaded
         correctly. Once you are sure the image has been written you
         can proceed to power off the device.
 4. Hold the reset button and power on the device. This will immediately
    begin downloading the appropriate initramfs image and boot into it.
    Note: If the device does not download the initramfs, this is likely
    due to the interface not being brought up in time. Changing Ethernet
    source to a router or switch will likely resolve this. You can also
    try manually setting the link speed to 10Mb/s Half-Duplex.
 5. Once a solid white LED is displayed on the device, continue to the
    UART installation method, step 6.

Standard installation via UART - MR42 & MR52

 1. Disassemble the device and connect a UART header. The header pinout
    is as follows:
      1 - 3.3v
      2 - TXD
      3 - RXD
      4 - GND
    Important: You should only connect TXD, RXD and GND. Connecting
    3.3v may damage the device.
 2. Set your IP to 192.168.1.250. Set up a TFTP server serving
    openwrt-ipq806x-generic-meraki_(mr42|mr52)-initramfs-fit-uImage.itb.
    Separately obtain the respective sysupgrade image.
 3. Run the following commands, preferably from a Linux host. The
    mentioned files, including ubootwrite.py and u-boot images, can be
    obtained from [1].
      `python ubootwrite.py --write=(mr42|mr52)_u-boot.bin`
    The default for "--serial" option is /dev/ttyUSB0.
 4. Power on the device. The ubootwrite script will upload the image to
    the device and launch it. The second stage u-boot will in turn load
    the initramfs image by TFTP, provided the TFTP server is running
    correctly. This process will take about 13 minutes. Once a solid
    white LED is displayed, the image has successfully finished
    loading. Note: If the image does not load via TFTP, try again with
    the Ethernet link to 10Mb/s Half-Duplex.
 5. (MR42 only) Do not connect over the network. Instead connect over
    the UART using minicom or similar tool. To replace u-boot with
    the network enabled version, please run the following commands.
    Note that in the provided initramfs images, the u-boot.mbn file
    is located in /root:
    If you have not used the provided initramfs, you must ensure you
    are using an image with "boot_layout" ECC configuration enabled in
    the Kernel. This will be version 5.10 or higher. If you do not do
    this correctly the device will be bricked.
      `insmod mtd-rw i_want_a_brick=1
       mtd erase /dev/mtd8
       nandwrite -pam /dev/mtd8 /root/mr42_u-boot.mbn`
    After running nandwrite, ensure you observe the following output:
      `Writing data to block 0 at offset 0x0
       Writing data to block 1 at offset 0x20000
       Writing data to block 2 at offset 0x40000`
 6. (Optional) If you have no further use for the Meraki OS, you can
    remove all other UBI volumes on ubi0 (mtd11), including diagnostic1,
    part.old, storage and part.safe. You must not remove the ubi1 ART
    partition (mtd12).
      `for i in diagnostic1 part.old storage part.safe ; do
       ubirmvol /dev/ubi0 -N $i
       done`
 7. Proceed to flash the sysupgrade image via luci, or else download or
    scp the image to /tmp and use the sysupgrade command.

[1] The mentioned images and ubootwrite.py script can be found in this repo:

   https://github.com/clayface/openwrt-cryptid

[2] The modified u-boot sources for the MR42 and MR52 are available:

   https://github.com/clayface/U-boot-MR52-20200629