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The U2 is a USB power meter and tester.
It is full of features and makes it the most complete USB power meter I known of:
The manufacturer is called WITRN. The device was first called WEB-U2, but now they registered the trademark/brand Qway to fight piracy.
The official website is rather empty.
It only point to the user guide and software (with broken link).
Instead they recommend to follow the QQ group 313755927.
Here links I could gather to get the latest version of:
There are several versions of the hardware.
The original manufacturer blocked this device.
After flashing firmware version 5.5, the display would just show
104083 ERR, and the device would not work anymore.
Moreover it was not possible to re-flash it anymore.
Thus don't install firmware version 5.5 of later if you have a device with serial 104083, else you will brick it.
Software version 4.0 or later also do not work with this device. You need to use version 3.0.
This device can still be used to measure voltage and current, but since there is no update anymore it will not be able to be used to detect charger profiles.
There is also a footprint for an Bluetooth adapter behind the screen, but it was not placed yet (the software was probably not ready).
I read out the FRAM (where the settings are stored) but did not find the serial number in there. I also cleared it to confirm the serial is not stored in the FRAM, but in the firmware. Sadly the firmware is read protected.
Debug header pinout:
_________ __|8 6 4 2| |9 7 5 3 1| -----------
Because the clone was bricked, I got a genuine replacement.
A Bluetooth module could be placed on the front side of the bottom board. The front board could also be light bz LEDs from the back side.
The U2p version is a variant of the U2 with 4 button instead of 2, and a switch to enable Power Delivery probing
Finally it was also possible to get a version with Bluetooth and some light next to the USB input (not sure when it is on though)
Here a list of the components present on the Qway U2p V1.1 board:
Here a couple of notes about the PC software (for Windows).
The software is in Chinese, but you can change it by translating the words in the
Here the english lang.ini (works for versions 4.0, 4.1, 4.4).
When started, the software will query http://www.witrn.com/updata/U2_NewVersion.pdf to get the latest version information.
This is not a pdf. I think this is just to pass firewall (just like they use HTTP without SSL).
This URL will return a short binary string, for example
0x44 0x67 0x25 0x11 0x12 0x12 0x13 0x21:
0x44: Software version 4.4
0x67: U2 Firmware version 6.7
0x25: X Firmware version 2.5
0x11: C3 Firmware version 1.1
0x12: C1 Firmware version 1.2
0x12: C0 Firmware version 1.2
0x13: C0s Firmware version 1.3
0x21: A0 Firmware version 2.1
If will also query http://www.witrn.com/updata/U2_ad.pdf, which is again not a pdf, but the text to display on the left side.
Using the Network upgrade it will also download the Firmware for the U2 at http://www.witrn.com/updata/U2_FW_NEW.pdf and U2p at http://www.witrn.com/updata/U2_4KEYS_FW_NEW.pdf (raw binaries)