SMSL SU-X FW Upgrade

[mikolajek]

Has anyone sucessfully upgraded their SU-X to FW 2.1 offered on the manufacturer's site? I'm trying to do so, following the instructions outlined in the attached PDF file, but I cannot succeed.

After I install the WCID driver and power up the DAC in the upgrade mode, I run the batch file (load.bat) but keep getting the message "AllWinner UAB FEL device not found!"

The PDF instruction says "connect the DAC to the computer via USB mini cable", but the DAC has no USB mini input port! :O I tried to upgrade it via the USB-B port and USB-C port and each time I see the same error.

Can anyone help, please?

 

[mikolajek]

@SMSL-Mandy, will you be able to help here?

I'm also wondering if I may already have MCU 2.1 on board. My device was received in May 2025, and I understand the upgrade file is dated for September 2024. Not sure how to check it, I don't see a menu option allowing for this.

 

[hxcn]

I just managed to get my SU-X upgraded sucessfully and you can check your firmware version on reset page.
The official guide is also not working for me.
1. After connect the dac with USB-B and power on the dac when holding the knob (a red light on without any screen display), you will find some sort of unknowning device in device manager.
2. Open the zadig-2.8.exe and goto Options -> List All Devices then you will find lot's of connected usb devices listed there, select the "unknowning device" in step 1 and choose and click "install wcid driver" then wait for the installation to complete.
3. Execute the load.bat and wait for the upgrade to complete

I tried many ways to get this upgrade working so I don't remember the steps clearly, maybe reboot between step 1 and step 2. You have to make sure this "unknowning device" have wcid driver installed before step 3 and you can check this in device manager.

 

[Tutonunez23]

Hello everyone.

I finally managed to update my SMSL SU-X to version 2.1 240925. Here's what worked for me:

1. Install the latest XMOS USB Driver from the SMSL website.

2. Download the firmware files from the SMSL website.

3. Install zadig-2.8 (without selecting anything).

4. ONLY NOW CAN WE START USING THE SU-X
5. Connect the USB cable (from USB B DAC to USB A on the PC). Use your best cable to be sure. It must be connected to the motherboard's USB port, not an extension cable. Connect the SU-X to a power strip with an on/off switch. Turn on the SU-X and select USB B input.

6. Turn off the SU-X using the rear panel.

7. Now you need to put the SU-X into firmware loading mode.
8. With the power strip off and the SU-X plugged in, turn on the power of the SU-X, then press and hold the round button on the front panel, and then turn the power strip back on. Only one red light on the SU-X's front panel will illuminate.

9. Run Zadig 2.8 again. An unknown device should appear in the program's tab (this is the DAC). Proceed with the WCID Driver installation. Wait for it to install.

10. Then turn off the SU-X using the rear panel switch.

11. Turn off the power strip using the power strip switch.

12. Put the SU-X back into Firmware mode: With the power strip off and the SU-X plugged in, turn on the power of the SU-X, then press and hold the round button on the front panel, and then turn the power strip back on. Only one red light on the SU-X's front panel will illuminate.

13. Now run LOAD. It should recognize it and begin loading three rows, reaching 100%. Wait, and you're done.

Note: It should work perfectly. If not, run SUNXI-FEL after step 8 and then continue from step 9 onward.
I wish you the best of luck!!!
I did this because the instructions on the official website are wrong and say it should be done via micro USB (which the SU-X doesn't have), and I always thought it meant USB-C.
Improvements:
- Absolutely stable I2S.

- No more (TERRIBLE) digital pops when changing songs with different bitrates. It was horrendous between 44.1 and 192 kHz… Only in I2S.

- Also via I2S, there are no more interruptions when playing DSD files.

- The menu is more user-friendly and visible.

- It only has four languages: English, Chinese, Russian, and another one that looks like Chinese… LOL

 

[mikolajek]

It did work this time (though I haven't used the power strip)! The only odd thing after powering on SU-X was that it got booted into Russian language

What I spotted immediately is that the knob is now much more responsive - the volume level changes quickly, while previously it required a lot more turning.

I liked the prior display theme better, though I agree the new is much clearer and visible.

I need more testing to check if the gurgling sound is still there when playing different bitrate files, but so far I haven't heard it anymore!

 

[Tutonunez]

I'm so glad you were able to install the update, Micolajek. That proves the process is repeatable, which is fantastic.
I listened several hours after the update, and all the crackling and flickering bugs were resolved with the new firmware.

 

[mikolajek]

It can be just my config issue, but after the FW upgrade I tend to believe the low-bitrate files' sound quality got worse...
I have some MP3 VBR ~200 and CBR 192 files with really old and/or hardly available albums, and they seem to be affected. The low tones got overwhelming...
No filter set on the SU-X, and only tiny EQ changes in my player (JRiver MediaCenter), not changed since the upgrade.

 

[Tutonunez]

I looked through old files for some 128 kbps MP3s and they sounded great. I have no idea what they sounded like before, haha, but they sounded pretty decent. It might be my Lumin and the U26...

 

[mikolajek]

Thank you, it seems it's just my DAC/AMP tandem that was affected. A small EQ correction did the job, and doesn't affect the overall sound!