ZBT WE-826 rebooting after a couple of minutes

Installing and Using OpenWrt
#1

Hi,

I bought a cheap ZBT WE-826 device, the one with metal casing, 16 MByte flash, MiniPCIe, and 128 MB ram...

First, I tried it with the stock firmware and i recognized that that thing was constantly rebooting after a couple of minutes.
Because I wanted 'my' OpenWRT from the begin with, I flashed it with the recovery option with the latest stable Version, as well as the latest trunk version.

The error remains the same, it boots up, has no errors neither in dmesg nor in syslog but suddenly stops responding via ethernet, holds a second and then reboots....

I already tested three different (known to be good) power supplies - the deliveres 12V 1A, also a 2 Amp and a 3 Amp PSU.
No difference....

The other thing I reconed was, after an Upgrade, when i login by ssh , change my root password and simply type a "sync" the box hangs! This time no reboot, only a freeze....

Maybe the flash is bad? But how to check?

Does anyone has the raw dump of the I²C EEprom, so I could simply change it and try again?

I thought this device would have a flaky wireless part, but that everything is as faky as that, I am a bit disappointed :frowning:

Cheers

att12

#2

You flash the "standard" image, without additional/extra packages, and this auto-boot occures ?
Have you a modem installed ?
I have lot of WE-826 set up, in various application scenarios, and only remember once to have had a similar effect. It was caused by the "watchdog" function, to reboot soon after boot, as I had a long-running rc.local, and the starup did not complete in expected time. Check the log, regarding procd messages. Startup completed ?
You might also set up a ssh-window, and "logread -f" to be shure, to catch last messages before boot.
Always being the very last one suspecting a hw-problem, in your case it might be one.

#3

You flash the "standard" image, without additional/extra packages, and this auto-boot occures ?

Correct. The ones which are on the openwrt download server (release and stable tested)

Have you a modem installed ?

Not yet. The pcie slot is still empty.

You might also set up a ssh-window, and "logread -f" to be shure, to catch last messages before boot.
Always being the very last one suspecting a hw-problem, in your case it might be one.

Oh I didn't mention it, but I did that as well.
There is no 'new' last message. Anything what was the last line still remains in the last line while it suddenly reboots.
I'll solder the serial port on the device and take a look there...

Or is there any kind of Hardware Watchdog which initates the reboot if something isn't right for him?
Think that device is too cheap for something like that.

Still... any Idea how to check the flash for badblocks? I remember on other devices there where shown on bootup or via dmesg, but on this device all seems good to me....

Another thought.... is it simple to put the openwrt rootfs on a microsd card, so the booting process switches after the initial boot to it? So I could rule out a bad flash as well.

Despite the fact that that kind of behaviour could be bad ram bad cpu or bad solder as well.....

Cheers

att12

#4

You might also be running out of memory after a while, so monitor that.
128MB is not that much anymore, so you might need to do a custom build with fewer elements.

#5

128MB is not that much anymore, so you might need to do a custom build with fewer elements.

with a out of the box trunk build? there is not even luci included. Don't think that could happen with 128 MB with a non-configured straight trunk built.

Cheers

att12

#6

Hi,

so I soldered the serial port on, but there is nothing unusual while it' is suddenly rebooting....:

[   25.703208] device eth0 entered promiscuous mode
[   25.740432] br-lan: port 1(eth0.1) entered blocking state
[   25.745990] br-lan: port 1(eth0.1) entered forwarding state
[   26.660817] IPv6: ADDRCONF(NETDEV_CHANGE): br-lan: link becomes ready
root@OpenWrt:/# logread -f



U-Boot 1.1.3 (Nov  9 2016 - 15:34:50)

SoC:MediaTek MT7620 
DRAM:  Memory Testing..131072K OK. is 128 MB
relocate_code Pointer at: 87fb0000
enable ephy clock...done. rf reg 29 = 5
SSC disabled.
spi_wait_nsec: 29 
spi device id: ef 40 18 0 0 (40180000)
Flash: W25Q128BV
*** Warning - bad CRC, using default environment

 _______________________________________________________________ 
|    ____                 _                 ____               |
|   |  _ \ __ _ _ __   __| | ___  _ __ __ _| __ )  _____  __   |
|   | |_) / _` | '_ \ / _` |/ _ \| '__/ _` |  _ \ / _ \ \/ /   |
|   |  __/ (_| | | | | (_| | (_) | | | (_| | |_) | (_) >  <    |
|   |_|   \__,_|_| |_|\__,_|\___/|_|  \__,_|____/ \___/_/\_\   |
|                                                              |
|                  Ralink/MTK SDK Plantform                    |
|                    Copyright 2005-2013                       |
|                    Board:MTK MT7620A EVB                     |
===============System Info================== 
ASIC 7620_MP (Port5<->None)
DRAM component: 1024 Mbits DDR, width 16
DRAM bus: 16 bit
Flash component: SPI Flash
CPU Speed: 580 MHZ
RAM Size:128 Mbytes

Build Date:Nov  9 2016  Time:15:34:50
============================================ 

GSW VLAN:LLLW 

GPIO Init:
        UARTF_SHARE_MODE:GPIO
        I2C_GPIO_MODE:GPIO
init gpio20!
----------------------------------------

 64M-ROM------------------------
Uboot version 1.3 ---zbt826-256M flash

---------------------------------------
GPIO_MODE_REG:0x1a311d
ReadyLED Bit:0x200

Please choose the operation: 
   1: Load system code to SDRAM via TFTP. 
   2: Load system code then write to Flash via TFTP. 
   3: Boot system code via Flash (default).
   4: Entr boot command line interface.
   7: Load Boot Loader code then write to Flash via Serial. 
   9: Load Boot Loader code then write to Flash via TFTP. 
 0 
   
3: System Boot system code via Flash.

Press Reset button enter upgrade mode!
## Booting image at bc050000 ...
   Image Name:   MIPS OpenWrt Linux-5.4.66
   Image Type:   MIPS Linux Kernel Image (lzma compressed)
   Data Size:    2083505 Bytes =  2 MB
   Load Address: 80000000
   Entry Point:  80000000
   Verifying Checksum ... OK
   Uncompressing Kernel Image ... OK
No initrd
## Transferring control to Linux (at address 80000000) ...
## Giving linux memsize in MB, 128

Starting kernel ...

[    0.000000] Linux version 5.4.66 (builder@buildhost) (gcc version 8.4.0 (OpenWrt GCC 8.4.0 r14548-620f9c7734)) #0 Wed Sep 23 10:17:32 2020
[    0.000000] Board has DDR2
[    0.000000] Analog PMU set to hw control
[    0.000000] Digital PMU set to hw control
[    0.000000] SoC Type: MediaTek MT7620A ver:2 eco:6
[    0.000000] printk: bootconsole [early0] enabled
[    0.000000] CPU0 revision is: 00019650 (MIPS 24KEc)
[    0.000000] MIPS: machine is Zbtlink ZBT-WE826 (16M)
[    0.000000] Initrd not found or empty - disabling initrd
[    0.000000] Primary instruction cache 64kB, VIPT, 4-way, linesize 32 bytes.
[    0.000000] Primary data cache 32kB, 4-way, PIPT, no aliases, linesize 32 bytes

The only things I thing a questionable are:

and

Uboot version 1.3 ---zbt826-256M flash

Even in failsave Mode it reboots itself after a couple of seconds/minutes

  _______                     ________        __
 |       |.-----.-----.-----.|  |  |  |.----.|  |_
 |   -   ||  _  |  -__|     ||  |  |  ||   _||   _|
 |_______||   __|_____|__|__||________||__|  |____|
          |__| W I R E L E S S   F R E E D O M
 -----------------------------------------------------
 OpenWrt SNAPSHOT, r14548-620f9c7734
 -----------------------------------------------------
root@(none):/# [   17.700574] random: crng init done
[   25.557615] 8021q: adding VLAN 0 to HW filter on device eth0
[   25.581639] br-lan: port 1(eth0.1) entered blocking state
[   25.587255] br-lan: port 1(eth0.1) entered disabled state
[   25.593191] device eth0.1 entered promiscuous mode
[   25.598146] device eth0 entered promiscuous mode
[   25.632664] br-lan: port 1(eth0.1) entered blocking state
[   25.638220] br-lan: port 1(eth0.1) entered forwarding state
[   26.573070] IPv6: ADDRCONF(NETDEV_CHANGE): br-lan: link becomes ready


U-Boot 1.1.3 (Nov  9 2016 - 15:34:50)

SoC:MediaTek MT7620 
DRAM:  Memory Testing..131072K OK. is 128 MB
relocate_code Pointer at: 87fb0000
enable ephy clock...done. rf reg 29 = 5
SSC disabled.
spi_wait_nsec: 29 
spi device id: ef 40 18 0 0 (40180000)
Flash: W25Q128BV
*** Warning - bad CRC, using default environment

The environment variables are defaulted...

U-Boot 1.1.3 (Nov  9 2016 - 15:34:50)
MT7620 # help
?       - alias for 'help'
bootm   - boot application image from memory
cp      - memory copy
erase   - erase SPI FLASH memory
go      - start application at address 'addr'
gpio     -set gpio pins
gpiotest         -test gpio pins
help    - print online help
httpd   - start uHttpd for firmware upgrade.
ledoff   -set led off
ledon    -set led on
loadb   - load binary file over serial line (kermit mode)
md      - memory display
mdio   - Ralink PHY register R/W command !!
mm      - memory modify (auto-incrementing)
nm      - memory modify (constant address)
printenv- print environment variables
reset   - Perform RESET of the CPU
rf      - read/write rf register
saveenv - save environment variables to persistent storage
setenv  - set environment variables
tftpboot- boot image via network using TFTP protocol
version - print monitor version
MT7620 # printenv
bootcmd=tftp
bootdelay=1
baudrate=115200
ethaddr="00:AA:BB:CC:DD:10"
ipaddr=192.168.1.1
serverip=192.168.1.100
preboot=
netmask=255.255.255.0
stdin=serial
stdout=serial
stderr=serial
ethact=Eth0 (10/100-M)

Environment size: 206/4092 bytes
MT7620 #

but even staying in the bootloader, the device resets itself after a short time.... whith no error on the serial whatsoever...

Hmm... any hints?

cheers

att12

#7

After trying everything I could think of but isn't worth the device, I gave up... Now it hangs on the wall...

I tried:

  • check PSU for CPU and Board, but all voltages were perfect no glitches whatsoever
  • changed the SPI Flash
  • reflowed RAM
  • reflowed CPU
  • try to force the reboot by mechanical bending, icespray or hot air, nothing changes

Maybe CPU or RAM is flawed, I don't know... It's not really worth changing any of that....

Funny though, a couple of weeks ago I wondered that even the cheapest chinese gadgets are normaly not DOA these days - that what worse 20 or even 30 years ago... GOTCHA :slight_smile:

Cheers.

att12

#8

I suspect, you had some very special bad luck. Having various clients (WISPs and ISPs), running commercial hotspots on WE-826 (plastic case) or using them for their wired customers, I never heard of such problems. But always there is a "first".