Debrick instructions / guide

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Debrick instructions / guide

Thu Apr 20, 2017 9:13 pm

Hi everybody,

we accidently bricked a vocore2 by flashing a completely wrong file.(yes! - this shouldn't happen, but, well, let's say it was late and it just happened).

I have an USB/UART converter at hand and a BusPirate as well (which quite often turned out to be a really nice tool).
Now I'm seeking for a good hint how to proceed.

I reviewed the tutorials and found a bunch of ways to go, but I am really missing a comprehensive guide that also outlines the boot process. The later would be very helpful to clearly identify what has gone wrong (Is the boot loader still intact? Is the kernel damaged? Is it a filesystem issue only?)

Since I found no satisfactory document about the topic, I'm willing to write one.

May somebody be so kind and direct me to the neccessary information sources?

Thanx in advance


Posts: 720
Joined: Sun Oct 19, 2014 6:00 am

Re: Debrick instructions / guide

Thu Apr 20, 2017 11:52 pm

I guess the uboot is still working.

1. connect your VoCore to computer through microUSB, keep your VoCore in reset mode.

note:: to keep VoCore in reset mode, you need to connect RST and GND by wire, use this step to wait until USB2TTL ready.

2. open tty tools(must have kermit protocol), such as kermit, ckermit.

note:: VoCore2 GD32 USB2TTL is driver free, but have to wait 6~8 seconds until it is ready, once it is ready, we can disconnect RST and GND, then it is able to boot normally.

3. power up your VoCore, once you find: "0: Load system code then write to Flash via SERIAL.", press '0'.

note: VoCore will show "## Ready for binary (kermit) download to 0x80100000 at 115200 bps..."

note: kermit: press Ctrl and '\' same time then press 'c', you will switch to kermit command console.

5. send upgrade firmware to VoCore, after that, back to VoCore uboot console.

note: kermit: call "send path/to/your/upgrade/file/on/pc.bin" to send firmware, around 10 minutes, once it finished, call 'c' back to console.

6. wait around 20~30 seconds, firmware uploaded, your VoCore will reboot.

Which point stops you? It is at

Posts: 240
Joined: Sat Nov 29, 2014 3:22 pm

Re: Debrick instructions / guide

Sat Apr 22, 2017 1:28 am

You mention a usb/uart converter so I am guessing you may have a single board (no built in converter).

If true:
1. Download 20161224.bin (known good, you can swap to something else later)
1. Connect usb/uart to txd2 and rxd2 on the left side (the one with 16 holes) don't forget to swap txd and rxd between the converter and the vocore.
2. Connect to the usb/uart with kermit
3. Apply power to vocore
4. Send 20161224.bin with option 0 on uboot menu

If you do use a bare board, the uart on the vocore is capable of communicating at 460800 baud (some usb/uarts can't) it makes the process much quicker. To change speed use uboot console with option 4 on the uboot menu then:

Code: Select all
setenv baudrate 460800
2. change to 460800 on the usb/uart, hit enter
Code: Select all

When uboot comes back up it will be running at 460800 baud.

If you have a USB host connector or ethernet (ultimate or homemade) try this

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Joined: Fri Apr 14, 2017 9:55 pm
Location: Germany

Re: Debrick instructions / guide

Mon May 08, 2017 1:51 pm

Thanks a lot for the advice. We managed to replace the bad image with a working firmware. Great.

The most comfortable way to go was via a prepared SD card for us.

Using the serial line with kermit made us some more trouble at first. I'm usually using minicom on my linux box and running kermit directly from minicom still runs into some problems. Does anyone have experience with minicom/kermit?

We also investigated using tftpboot but yet without success. The tftp-server reports an access and willingly sends the file. But apparently vocore doesn't like it and repeats its request. Is that a known problem or merely work in progress?



Posts: 11
Joined: Fri May 26, 2017 7:59 am

Re: Debrick instructions / guide

Sun May 28, 2017 8:40 pm

in this post you can find full procedure

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