[Pál Bakula]

Could somebody who owns a working hub measure the resistor between pin4 (sense) and pin5(GND) and between pin4 and pin1(VCC) of the USB connector. (The second measurement is expected to be infinite ohms.) I’d like to try to make my own Y-cable. Thanks!

[Pál Bakula]

Hi, cheah,

Thanks for the serial number. Did yours came with dual OS?
The tool I used is an FTDI FT2232H mini module wired to the SPI flash.
I use it since I soft bricked the tab with the unofficial dual boot bios.

Regards

[Pál Bakula]

I flashed the new official dual boot BIOS with an external HW tool.
It’s not compatible with my Hi8 Pro. Blank screen.
My SN is 34XX.

Could someone who owns a dual boot device post the serial number.
I guess Chuwi modified something in the HW to fix the issues we (their beta testers) facing.

[Pál Bakula]

In the USB hubs there’s usually a diode to prevent the power current flow from devices to host.

I own an USB 2.0 hub with external power. I disassembled the hub an soldered a jumper over the diode.

I attached the hub to a USB-C – USB-A female cable and the charger to the external power input of the hub and it works.

It also works if tha charger is connected to a device port with a USB-A male – USB-A male cable (USB extension cable  + USB-A male-male gender changer).

[Pál Bakula]

Mine is not stable despite it’s 1538.

By the way the ‘mystical’ number is the manufacturing date code of the IC.

Mine was manufactured on the 38th week of 2015.

I personally don’t think that there would be a connection between the ‘stability’ – or call it whatever – and the date code of the SPI flash IC (BIOS).

 

[Pál Bakula]

@dawei:

Aptio V afuwin rejects flashing this rom. I used a different tool to flash and brick my Hi8 pro.

I can share how I flashed this rom, but it bricked my tablet.

Likely it’s recoverable by reprogramming the bios chip with an eeprom programmer.

I got one. And you…?

[Pál Bakula]

It’s from 15:11:14 01/22/2016.

I extracted some parts of this rom with MMTool and found the previous build date.

I also found the “Hi8Pro” and “x64” strings so at least it’s really for our tab (even if it’s not starting properly for me).

 

[Pál Bakula]

@Chris G:
My serial number is 3000+

[Pál Bakula]

Hi!

I do not recommend flashing this bios. I did it 2 days ago with a windows tool.

• Now the screen does not turn on.
• It tries to read something from the USB stick connected through a hub which also powers the tab but stops after 5 secs.
• No LED signalling at all.

At least I made a backup and I have a professional EEPROM programmer.
…but no T4 screwdriver yet 🙁
 

Here’s how to make a backup: fptw.exe -D biosbackup.rom

—–
Paul

[Author]

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