KuWfi 830D - Which "target"?


#1

Hi,
I have this device

Can I compile OpenWrt with Yuncon 830 ? Or which target is correct ?

thank you


#2

Chipset: QCA9531

That's an AR71XX chip. It may be the "CPE830" build in ar71xx/generic. Maybe.


#3

Yes maybe.

In the event I upload it and the device refuses to boot, how can I upload another built ? Is there a way to make it from u-boot ?


#4

THis look very very similar to http://yuncore.com.cn/en/ProductDetail/2228452.html#


#5

Good first steps would be to get console access and explore what is available in the boot loader. Only if you can confirm that you can, for example, flash an image from a TFTP server from the boot loader would I try a "random" image.


#6

No console access, the seller refuses to give the root password


#7

The bootloader console. You will need to connect to the serial port inside the case.


#8

How to acheive that ? And where can I find a serial port nowadays to do TFTP?


#9

Once you have serial port / console access you can issue commands to do tftp etc over Ethernet


#10

Great but how to acheive this. Nowaways, serial does not exist on a computer. And supposedly, there would be a serial connector on the device (which also does not exist for ages already)


#11

I read here ( https://wiki.archlinux.org/index.php/Dnsmasq#TFTP_server ) that dnsmasq has TFTP capabilities, and the device has dnsmasq running (as I can see in the small logs provided by the existing firmware)

Is that the way ? Or do I need a physical serial port (which seems pre historical) ?


#12

Read carefully about USB to 3.3 V serial adapters as many on the market are "TTL" or "RS232", both of which will likely fry your SoC.

There are typically test points on the board to which you can connect RX, TX, and ground. You will need to open the device and determine the proper logic level, as well as the holes, pads, or pins involved.


#13

No planning to do welding on a 40 dollars device !


#14

"Flash and pray" then is the other option, as you may well brick it and a serial connection will be your only hope for recovery (short of having a backup of the ROM and the tools to flash one without a boot loader).


#15

Don't get it. TFTP is IP protocol. Completely lost about your serial story.


#16

Boot loader is controlled over serial. U-Boot and other boot loaders typically have a command that downloads an image over Ethernet from a TFTP server and flashes it to the ROM.

Unless you can luck into determining how to get the boot loader into TFTP-download mode (if it exists at all), what the target IP address is, and what file name it is looking for, you'll need serial access to the boot loader.


#17

Don't get it. What is "serial access to the boot loader" -> The boot loader is not a physical thing, it is a softwre on the device. Why should I do welding and connect a Serial (if ever it is even produced somewhere) to connect to what ?


#18

That is correct, and when that software runs, it typically provides output to the serial port and accepts input from the serial port.

Before going further, I would strongly suggest that you take the time to read up on how to work with, for example U-Boot.


#19

Yeah, but any doc refer to some serial port. Of course I dont have any. I am totally lost here


#20

Using a serial port to connect to a device allows access to the device to control it and get status without needing a Ethernet or WiFi connection.

If for example you did something to prevent Openwrt or OEM firmware working correctly and you have lost access to the router via Ethernet or WiFi , you can use a serial connection and while the device is booting and still in U-Boot for example you could press a key on the console to stop the process in the bootloader and prevent openwrt etc from starting. Then some boot loaders have some simple function such commands to use TFTP to download a file other Ethernet connection and then test that firmware from ram to verify or just write it to flash and reboot the device.

The main purpose of the serial console is to gain access to the bootloader at start up. Obviously on a working system you could also use it to access openwrt although in that case you would normally just use ssh.