[XTF1]

Thank you! I have been looking for this. Do you happen to know the procedure for the zishan md2 too?

I’m pretty sure the tool & procedure would be the same for md2: I don’t see why the Amanero CPU FW would be any different on md2 (or Z4). However the CPLD FW is probably different between U1 and md2: USB audio only of U1, + Bluetooth, +SD files on md2 (or Z4).
Note that although great, this tool only takes care of the Amanero part of U1: the STM8 (or STM32 on md2/Z4) is completely separate and would require a ST programmer to update the U1: I believe that’s the 4 pads you see on the picture..

 

[rolex0329]

Thanks for posting this tool!
I tried to update the FW on my older (~Jun 2020) AK4493 U1.
Good news: it worked with no issue, I did not brick the U1 !!!
Not so great news: it did not change the behavior of this older U1–cannot connect to my laptop through a USB-C hub (but does connect directly), and is not recognized by my Tempotec V1A. I tried the “DSD512x48x44” as shown and “firmware_2006be11” (the latest version on Amanero website?) with no difference that I could notice.
I haven’t tried all the FW versions supported in the tool; is “DSD512x48x44” the latest FW (I doubt it…) ???

It is not possible to assume the situation of playing through DAP. As for the supported range of firmware, if you change the OEMID that appears when you run ConfigTool.exe to NATIVEDSD, there is a more recent firmware.

CPLD_1082 series and 2006be15 series are firmware that can be flashed in nativedsd. This caused a problem when converting the number of bits of the sound source when it was played on an Android player with USB OTG. It may be helpful for recognition in DAP.

 

[XTF1]

It is not possible to assume the situation of playing through DAP. As for the supported range of firmware, if you change the OEMID that appears when you run ConfigTool.exe to NATIVEDSD, there is a more recent firmware.

CPLD_1082 series and 2006be15 series are firmware that can be flashed in nativedsd. This caused a problem when converting the number of bits of the sound source when it was played on an Android player with USB OTG. It may be helpful for recognition in DAP.

Thanks again for the information
I reflashed my older U1 AK4493 with CPLD_1082_DSDSWAPPED and firmware_2006be15r2. It worked… … but no difference as far as DAP or USB-C hub recognition (not recognized, same as before).
I also tried firmware_2006be15r6, r7 but these did not work (error in W10). be15r2ekv works but did not notice a difference with be15r2
On the CPLD side, I also tried “CPLD_1082” > works with PCM content, not sure about DSD content (did not try).
Oh well… I tried!

 

[captione]

WARNING: If you can't tolerate damage to your device while performing this mod, please don't try, I just posted how to do the mod.

We would like to give you a brief introduction on how to replace the firmware of Zishan U1.

First, disassemble U1, carefully remove the battery part attached to the motherboard, and then short the contacts shown in the photo with tweezers.

https://drive.google.com/file/d/15KFVRrOatjb1CrFUDpOp12IkckLEsJx9/view?usp=sharing

The Amanero chipset used in the U1 is a clone and requires a modified Amanero Config tool.

Just download the file from the Google Drive link above, unzip it,

If you reconnect U1 after shorting the contact, the LED light will not come on. After preparing Zishan U1 in this state, run ConfigTool.exe.


After setting CPLD Firmware to 1080 or 1081 and CPU Firmware to DSD512X48X44, press Flash CPLD and Flash CPU in order and wait.

If the device is recognized as Amanero Technologies USB Driver 1.0.67 in Device Manager, you are successful, congratulations.

When using Zishan U1's USB OTG mode, this MOD can solve the problem.

So with this tool, is it possible to mod the U1 FW to change its sound like changing filters, etc?

 

[XTF1]

So with this tool, is it possible to mod the U1 FW to change its sound like changing filters, etc?

Unfortunately no…. It can ‘only’ update the Amanero-like firmware—the Amtel MCU + CPLD that manages the usb DAC interface. The U1 internals such as the DAC configuration (filters etc.), standby timers, etc. are managed by a STM8 MCU. AFAIK, the firmware for that MCU is not available and it would require a ST programming tool to perform the update.
So this tool is great, but it only allows to choose between different Amanero-type FW. versions, with no real fine tuning options (not completely true as it supports some I2C custom commands, but I don’t think they do anything on the U1…)

 

[Setmagic]

U1 works with Apple stuff? Eg. iPhone, iMAC

 

[spbkaizo]

I just checked, and it doesn't work via Lighting <-> USB C cable with an iPhone (12 mini). This isn't unexpected though, I've struggled with a lot of USB C DAC's. I normally just use the apple dongle for audio on this.

It works fine with my MacBook Air M1 via USB-C connections.

 

[XTF1]

With iPhone yes, but you need either the (bulky) Apple camera connection kit (CCK), or an equivalent adapter/cable to enable “OTG-like” functionality. I have a ddHifi TC28i and it works fine. You may find some cheaper cable/adapter, but it’s a little bit of a lottery! I believe 24/96 is the max hires you can get on iPhone lightning connector (?)
I can’t answer for MAC’s, but the Amanero interfaces are reported to work fine with no driver needed, I assume it would be the same for U1 (or Z4, MD2).

 

[Setmagic]

It's great news @spbkaizo and @XTF1.
I'm preparing another project, go for 2x U1 ESS9038 version and I will put the trigger and mod it as much as possible.
All caps, resistors, LDOs, opamps and better pot.

 

[buchokoy]

hi guys, what is the line out voltage of the u1? thanks

 

[Setmagic]

2V its standard @buchokoy

@edit
In U1 board there is I2S connections, it is working as IN or OUT? Will be work with some nice BT receiver?

 

[Setmagic]

I got answer form Zishan it's a I2S output so it's can deliver to another DAC via I2S.

I made some mods on U1 as well.

• Texas Instruments LDO LP5907
• Lpf AD8620
• Amp Opa1612
• Capacitors in analog C0G 100nF and 10uF X7R MuRata
• Ultra low ESR Rubycon LZH 330uF 35V for main opamp
• Resistors 3 ohm insted 10 in output
• Removed blocking caps

 

[XTF1]

I made some mods on U1 as well.

• Removed blocking caps

Removing blocking caps: I thought U1 output stage was class AB. Don’t you get 1/2 of the rail DC into your headphones (~4.5V)?

 

[Setmagic]

Removing blocking caps: I thought U1 output stage was class AB. Don’t you get 1/2 of the rail DC into your headphones (~4.5V)?

Its just passive filtering 220uF its hi-pass filtr and DC block, it's shorted so still same power.

 

[XTF1]

Its just passive filtering 220uF its hi-pass filtr and DC block, it's shorted so still same power.

I agree with the hi-pass filtering part, but was concerned about the risk of frying the headphone or IEM: I believe U1 amp power supply is 0 / +9V (it’s not symmetrical) so without blocking cap, 4.5V DC is flowing through the headphone…. But it may not be a problem after all!