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Uboot does not respond to 'x'

Posted: Mon Mar 30, 2015 9:07 pm
by Ton
Hi, I sysupgraded with an image that was not too well done, it does not start up. Now I want to reflash through u-boot.
But whatever I do, I can not get the boot process to recognise the x and go to uboot.
I have tried multiple terminal programs and usb-rs232 thingies.

Anybody an idea what to do?

And, if this will not work, is there a way to flash it right again, like with JTAG?

Re: Uboot does not respond to 'x'

Posted: Tue Mar 31, 2015 1:26 pm
by noblepepper
This sounds similar to problems I was having with uboot that were caused by a bad solder joint I made, it took very close inspection to find but once I resoldered it all was fine. Inspect the uart connection under magnification to be sure it is good. JTAG is possible but not so simple evidently..

Does your image get far enough that you can trigger failsafe? How does it fail?

Were you able to stop uboot before the Sysupgrade?

How did you do the sysupgrade? SSH? Luci?

Do you have the dock or a bare VoCore, maybe with Greenewire's breakout board?

Re: Uboot does not respond to 'x'

Posted: Thu Apr 02, 2015 2:43 am
by Vonger
Hi, that might be USB2TTL is not well connect to GND. USB GND and VoCore GND must connected.

Re: Uboot does not respond to 'x'

Posted: Mon Apr 06, 2015 6:46 pm
by Ton
The connection is fine. I double checked. I also did not power up, but reset with the reset pin to ground.

It seems that there is no delay anymore. the sentence "Press 'x' for console" is printed, but I think it actually does not check for any character.
Does anybody with U-boot knowledge know if that sentence is always printed, even when bootdelay = 0?

Re: Uboot does not respond to 'x'

Posted: Tue Apr 07, 2015 1:44 pm
by noblepepper
Unless you did something like
Code: Select all
setenv bootdelay 0

uboot will use a compiled in default which was 1 second on my VoCore when I received it.

If you did set it to 0 the stock Ralink u-boot would print the prompt, then start to wait (in this case for 0 seconds). The source to the uboot actually loaded on the vocore is lost but it is very likely to use the same flow.

You can see the original Ralink u-boot code at github, the interesting bits for this are at lines 1735 where it actually waits and 735 where it prints the prompt.

It can be tricky catching the 1 second delay, I plug in the usb-ttl adapter, start the serial terminal program, then type "xxxxxxxxxx" while applying power to the VoCore. I understand the desire for a quick boot up but I always set my boot delay to at least 5 seconds to avoid this difficulty.

Re: Uboot does not respond to 'x'

Posted: Tue Apr 07, 2015 6:39 pm
by noblepepper
Try pressing "x" repeatedly while your image is trying to boot up, the console starts echoing very early in the boot process and you can see that your serial connection is working. If I do this I see this on the console:

[ 0.740000] 8021q: 802.1Q VLAN Support v1.8
[ 0.770000] VFS: Mounted root (squashfs filesystem) readonly on device 31:4.
[ 0.780000] Freeing unused kernel memory: 204K (802bd000 - 802f0000)
xxxxxxxxxxxxxxxxxxxprocd: Console is alive
procd: - watchdog -
x[ 7.970000] usbcore: registered new interface driver usbfs
[ 7.980000] usbcore: registered new interface driver hub
[ 7.990000] usbcore: registered new device driver usb

Re: Uboot does not respond to 'x'

Posted: Sat May 23, 2015 2:15 pm
by Ton
I was going to reflash this vocore with the dangerous stuff (flashrom), using a raspberry pi.
So I connected the SPI and also the UART to the raspberry. On the raspberry I used minicom for the internal uart.

When I started up the vocore I noticed I could see a 1 sec delay, and yes, now I got it responding to the 'x'.

In other words, if you can not get into u-boot, also try another PC/System.

And well, I never got to the dangerous stuff, I could reflash with uboot and it is working again. :)