Supporting ZSUN Wifi Card Reader (16MB Flash, 64MB RAM, AR9331)

If you have locked yourself out of your device without recovery and without serial access to U-Boot then I guess you have bricked your Zsun-SD100... =/

Unfortunately I can't help you with that situation, but perhaps someone else might have some suggestion.

I have soldered UART, but it inaccesible(. Can i flash spi flash without desoldering?

In this case it will be tricky, since the SPI flash is a QFN package. Maybe you can build something to make a contact to the pads.

The pre-compiled image for OpenWrt 19.07.3 (main firmware) and upgrade instructions are now available (link).

The documentation has also been updated with instructions on how to use the patches for the official OpenWrt Image Builder (link).


A big thanks to brunompena for putting together those detailed instructions and pre-compiled images. I was able to use them to upgrade from 15.05 to 19.07.03. Testing it in repeater mode I noticed Wi-Fi throughput was higher than on 15.05 (closer to 15Mbps instead of 10Mbps).

Since it's not directly linked in the above post, the specific instructions I used are linked here.


Does anyone have problems with using ftp with zsun running 18.06 or 19.07?
I have 2 devices running these versions and when i transfer files after 5 minutes the tranfer fails and the zsun reboot itself.
I also have a zsun running 15.05 and ftp is perfectly usable with this version, no reboot at all.
I tried to solve this problem with several solutions in vain.

@brunompena Just followed all upgrade instructions for for OpenWrt 19.07.3 and all went OK
When I try to boot into recovery the zsun led starts flashing very quickly but no Recovery SSID is showing .
Main firmware is accessible ... instructions to reflash the recovery image done 2 times md5sum matches.
But no recovery SSID.

Regards Benny

@0pointnrg Please double check that your device is detecting the SD card events correctly:

  • Disconnect your Zsun from the USB, eject the SD card but don't remove it
  • Connect your device to the USB and let it boot the Main firmware
  • Login to an SSH console and then type: logread -f -e sdcard_event
  • Try to push your SD card in (no need to lock it in place, just push it in for a second or two) and then let it go
  • If everything is working properly then you should see two messages similar to:
Sat May 16 18:36:39 2020 user.notice sdcard_event: SD Card inserted
Sat May 16 18:36:42 2020 user.notice sdcard_event: SD Card removed

If everything is detected correctly then please try once more the instructions to boot to the Recovery firmware:

  1. Disconnect your device from USB
  2. Eject the SD card but do not remove it (you'll need to push it back in during the initial boot process)
  3. Connect your Zsun to the USB
  4. When the LED flashes/blinks for the first time, immediately push the SD Card in (hold it for a second or two and then let go) to boot into the recovery image
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ok got timing right to trigger recovery ... I'm on the safe side now :slight_smile:

Thx Bruno


@brunompena Have you been able to compile a 21.02 image yet based on your patches?

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The pre-compiled image for OpenWrt 21.02.0-rc4 (main firmware) and upgrade instructions are now available here.


Your pre-compiled image works flawlessly, thanks! Building an image by patching the imagebuilder doesn't work for me though... I can run the patch and build an image, but after flashing the image, WiFi doesn't turn on (so need to restore from recovery). Has anyone been able to use the imagebuilder yet?

I have re-checked the Image Builder patch and it looks to be OK (all files checksum match).
I also successfully built and tested an image using the instructions I have on the repository page:

IMAGEBUILDER_VERSION="21.02.0-rc4"    # OpenWrt version to build
IMAGEBUILDER_PACKAGES=""              # Test image with no package customization


wget -qO- "${IMAGEBUILDER_URL}" | tar xJvf -

patch -p1 < "${IMAGEBUILDER_PATCH}"
find files/ -type f -exec chmod 0755 {} \;

make image PROFILE="zsun_sd100" FILES="files/" PACKAGES="${IMAGEBUILDER_PACKAGES}" && \
echo -e "\n\nOpenWrt image was built successfully and can be found at:\n  ${IMAGEBUILDER_IMAGE}\n\n"

If I have to guess, you probably forgot to set the executable attribute to the files under files/.

Can you please try the above instructions (copy & paste) and see if that works for you?


I did the copy paste, but still resulted in an image that I could flash but wouldn't work. I then decided to create a new VM to run the imagebuilder in, and then the resulting image suddenly worked. So there must have been something odd going on in my old VM... Anyway, no issues with your patch and/or instructions :slight_smile:


Glad to hear you got it working!

Hi! Great work.

I haven use my Zsun after quite many years. I have right now the version:
LEDE Reboot 17.01-SNAPSHOT r2993+618-b9a408c

Could you let me know a safe way to upgrade to the last version you made?

Please follow the instructions on the found on the main repository page.

If you cannot identify your firmware version and you would still like to attempt the update, then I suggest the variant1 of the update firmware (be sure you want to go forward with it as you may brick your device!).

I have uploaded the patches and pre-compiled images for both main and recovery firmware:

Do not upgrade both at the same time, and only start the upgrade of one of them after you verified you can login to the other (so you can recover in case something goes wrong)!

  • Before upgrading the main firmware, be sure you can login to the recovery firmware.
  • Before upgrading the recovery firmware, but sure you can login to the main firmware.

Hello, I'm on 17.01-SNAPSHOT, r2993+618-b9a408c on kernel version 4.4.103. My md5sum is 27af1351fbae86a9066a38b3b2093216 and want to flash 21.02.0 + recovery. What should I do?

This is the exact same question as @jjrbfi did, just 3 posts above yours...

Based on your firmware version alone I can only guess you are still running the stock u-boot, for which you should use the variant1 of the update firmware (with all disclaimers attached).

The update firmware will make the following changes to your device:

  • Install a new u-boot
  • Install OpenWrt 19.07.0-rc1 as the main firmware
  • Install OpenWrt 18.06.5 as the recovery firmware

Once this is done, you may go ahead and upgrade both main and recovery to the most recent versions.