Netgear WNDR3700v4 unresponsive after upgrade to 22.03.0 (r19685-512e76967f)

Installing and Using OpenWrt
1

Hi all.
So after succesfully upgrading spare:
Netgear WNDR3800, Netgear WNDR3700v2 and Netgear WNDR3700v5 with no issues

Attempt to update Netgear WNDR3700v4 has resulted in unresponsive router.

I saved some copy & paste notes on the process.

Build downloaded from firmware selector:
About this build
Model:
NETGEAR WNDR3700 v4
Platform:
ath79/nand
Version:
22.03.0 (r19685-512e76967f)
Date:
2022-09-03 23:22:56

https://firmware-selector.openwrt.org/?version=22.03.0&target=ath79%2Fnand&id=netgear_wndr3700-v4

Existing install:

Model
NETGEAR WNDR3700v4
Architecture
Atheros AR9344 rev 2
Firmware Version
OpenWrt 19.07.4 r11208-ce6496d796 / LuCI openwrt-19.07 branch git-20.247.75781-0d0ab01
Kernel Version
4.14.195

Explanation: The checksums did match and every time previously I have seen a warning, the Force Flash has worked.
So I decided not to bother posting on here asking for reassurance.
With hindsight that is looking like an error now. :frowning:

Paste LUCI Flash page messages:

The flash image was uploaded. Below is the checksum and file size listed, compare them with the original file to ensure data integrity.
Click "Proceed" below to start the flash procedure.

    Size: 7.62 MB
    MD5: 9d0164ad4932081d1c04429c98019abe
    SHA256: 44def399fad516f537281db1971ceacb6159fe16fb55bda9313a586d0a4ce563
          
Keep settings and retain the current configuration

Device wndr3700v4 not supported by this image Supported devices: netgear,wndr3700-v4 Invalid sysupgrade file. Image check failed.

The uploaded image file does not contain a supported format. Make sure that you choose the generic image format for your platform.

Force upgrade

Select 'Force upgrade' to flash the image even if the image format check fails. Use only if you are sure that the firmware is correct and meant for your device!

The powered up LED remains flashing and router is powered up but no open ports.

Nmap scan report for 192.168.1.1
Host is up (0.00050s latency).
All 1000 scanned ports on 192.168.1.1 are in ignored states.
Not shown: 1000 filtered tcp ports (no-response)
MAC Address: A4:2B:8C:0C:AB:CD (Netgear)

Nmap done: 256 IP addresses (1 host up) scanned in 35.97 seconds

Have seen the device page here:

What advice to attempt to recover?
Will I be able to try TFTP or will I HAVE to attempt serial port?

Thanks.

2

fwiw, have you tried nmrpflash which can recover most Netgear routers?
https://openwrt.org/toh/netgear/wndr3700#oem_installation_using_nmrp_wndr3700v5

1 Like
3

Thankyou bill888

I had forgotten all about nmrpflash!

Will look at that. :slight_smile:

4

So I rescued this router by building nmrpflash and using it to flash first the previous stable factory version:
openwrt-21.02.3-ath79-nand-netgear_wndr3700-v4-squashfs-factory.img

This worked and I was able to update that as normal using the LUCI firmware updater.
first to openwrt-21.02.3-ath79-nand-netgear_wndr3700-v4-squashfs-sysupgrade.bin
then again to recent Latest:
openwrt-22.03.0-ath79-nand-netgear_wndr3700-v4-squashfs-sysupgrade.bin

So that spare router is useable again. :slight_smile:

However I still have the issue of updating an identical router that is actually in use.

When I attempted to update from

Model
NETGEAR WNDR3700v4
Architecture
Atheros AR9344 rev 2
Firmware Version
OpenWrt 19.07.4 r11208-ce6496d796 / LuCI openwrt-19.07 branch git-20.247.75781-0d0ab01

to recent stable via LUCI 'Flash new firmware image' to:
openwrt-21.02.3-ath79-nand-netgear_wndr3700-v4-squashfs-sysupgrade.bin

I see the scary warning:

Flash image?

The flash image was uploaded. Below is the checksum and file size listed, compare them with the original file to ensure data integrity.
Click "Proceed" below to start the flash procedure.

    Size: 7.19 MB
    MD5: cb63d18380f9963bffa25aef42a6f977
    SHA256: 2b9bb284f04a74f08e7a3afe34c606195903d561dace4154df0544f96e0997d2

Keep settings and retain the current configuration

Device wndr3700v4 not supported by this image Supported devices: netgear,wndr3700-v4 Invalid sysupgrade file. Image check failed.

The uploaded image file does not contain a supported format. Make sure that you choose the generic image format for your platform.

Force upgrade

Select 'Force upgrade' to flash the image even if the image format check fails. Use only if you are sure that the firmware is correct and meant for your device!

I did consider upgrading first to the last build in the 19.7 series but see there is some discontinuity in file path and naming because this version of the WNDR3700 is the one which uses nand memory

wndr3700v4 is not in 'generic' here:
https://downloads.openwrt.org/releases/19.07.9/targets/ath79/generic/

but I also do not see an image in 'nand' here:
https://downloads.openwrt.org/releases/19.07.9/targets/ath79/nand/

How can I proceed to upgrade from 19.07.4 without risking trashing this router too?
Any suggestions much appreciated.
Thanks. :slight_smile:

5

Hi.
The title says 3200v4 while you are talking about 3700v4 :wink:

I had issues with this router:

  • there is some kind of 8MB limit issue. Check the image file size.
  • I would recommand the reverse to stock firmware with nmrpflash, than flash a FACTORY image of 22.03. Once it's done you may be able to upgrade to future 22.03 releases. I had the same issue when going from 19.07 to 21.02. The issue may be related to the partition layout change.

Considering the memory print of 22.03, I have decided to keep such old devices to 21.02. Flash 22.03, compare, and make your own opinion about this.

6

Thanks badulesia

The title says 3200v4 while you are talking about 3700v4

DOH! fixed.

I would recommend the reverse to stock firmware with nmrpflash, than flash a FACTORY image of 22.03.

I did want to try that but was unable to navigate my way through the German language link provided to find an image to download. :frowning:

After a bit more persistence I have found the English support page.
I might as well post the links here as that way they might be of some use to another forum user searching in the future.

"Release notes"

I will have a think about which Image(s) to try.
I see that the decompressed Netgear .zip image is well over 8Meg.

$ ls -lh
total 9.1M
-rw-r--r--. 1 auser auser 3.4K Aug  3  2018 WNDR3700v4-V1.0.2.102.html
-rw-r--r--. 1 auser auser 9.1M Aug  3  2018 WNDR3700v4-V1.0.2.102.img
7

Yes that's the latest netgear firmware.

The 8MB flashing issue is only while upgrading OpenWrt. Original Netgear images have no issue while restoring with nmrpflash even if larger than 8MB.

About nmrpflash

  • deactivate your firewall (on windows at least)
  • doc says to power on the device THAN run the command line. I have found that I must run the command line THAN power on the device. Try both methods.
  • at last step, wait for the "reboot your device" message. Sometimes it took a long time (about 5 min), be patient.
  • you may have to do the whole process twice (can't tell you why).

Each time I was in a desparate situation with a netgear device, this program saves it.

Keep in mind that your device is old and sluggish. I would recommand to use is as an AP or a spare device. And as I told before, I decided to keep it under 21.02 for a lower memory print.

8

Hi
I have just upgraded the 3700v4 to version 21.02.3, and I realized that it has 128 MB of RAM. So it may be relevant to install 22.03.0 afterall. I will make tests another day.

10

Hi.
I have just upgraded a 3700v4 from 21.03.3 to 22.03.0, using sysupgrade within Luci. I was using a custom build, and everything went Ok. The memory imprint is correct, so the router is usable with 22.03.

Nevertheless, the image file is 7.8 MB. That means that only basic packages can be added to the default ones. So this router can only perform its basic purpose. That can't be too harsh, considering that this device is a vintage one.