Trouble

3 day old B-Pi seems to be dead......

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Post Last Edited by roses2at at 2014-9-17 07:55

Reply 10# sashijoseph

@sashijoseph
Well thanks, that seems fairly straightforward (at least easier than I thought it was going to be; it might not be quite so easy understanding and interpreting whatever - if any - boot messages I get).

The only USB-TTL cable I can find locally is almost 20 Euros!! Plus 6 Euros delivery or a 5 Euros return bus fare and a total journey/in-shop time of about 2 hours.


So I did (eventually) find the right one on Amazon for 2 Euros (link for Amazon cable), but the postage was another 3€ ..............oh, and it might take over a week to arrive. So no debugging for a little while.


While I have your attention, what is the K3 Uboot button for (located between CON2 and the back of Ethernet socket)? Is that also something to do with J11?

Cheers

OK, I think I (sort of, but not fully) answered my own question.

It seems you can boot up from a USB stick attached to the OTG port for debugging purposes.
http://forum.lemaker.org/viewthr ... amp;highlight=uboot Post #5
and
http://docs.cubieboard.org/tutor ... g_from_usb_otg_port

But the instructions in this link are not clear to me. I don't have a Linux computer to carry out all those Terminal commands, so where can I download the necessary files/image to put on my USB stick?

And excuse me for stating the obvious, but the link above is from a Cubieboard website. Are all the infos and instructions also totally and 100% relevant/accurate for the B-Pi simply based on the fact they both have the same SoC Allwinner A20 chip?

What exactly is the sequence to get into Uboot? Different websites give conflicting information? Will I see some sort of output on screen via HDMI as well as AV video, depending on which is connected? Or is that output only via a PuTTY terminal?

The way I understand it is so:
Power down and remove all cables and the SD card.
Wait a few seconds for the faint glow of the red LED to extinguish.
Plug in 5V/2A power supply adapter to a wall socket (which is switched off) and then into B-Pi's DC In.
First press and hold the K3 Uboot key (between CON2 and Ethernet socket) while switching on the wall socket.

Well, I tried all of that in any number of combinations, but no screen output. Perhaps that means my B-Pi really is dead as the proverbial [famous Monty Python sketch] if it doesn't even respond to Uboot.

That button serves to upload images to onboard NAND flash,if any.
you connect a usb cable between the PC and the board's OTG port,fire up the image transfer software on the PC,point it to the correct image file and then press the Uboot button on the board and the image is flashed into NAND.

Since the BananaPi doesn't have onboard Flash,needless to say this function is redundant.

But wait...there is another function for the key.
It allows you to boot over USB...no not your pen drive plugged into the usb port,but something like network booting.
You plug in a usb cable between the OTG and your PC's USB port and use a special tool from Sunxi to load a specially prepared uBoot,your script.bin and the kernel,while pressing the uBoot key when powering up the BPi.This boots up the kernel for you and then it can be tailored to mount the rootfs.

As you can see...pretty tedious way of starting your Pi,but may come in handy if your sdcard slot's gone kaput or sth.

For more,read up on FEL mode at Sunxi.org

As for the cable you could try Ebay if that's an option for you.

This,for one says "UK Stock" (dunno where you're located)
http://www.ebay.co.uk/itm/USB-to ... hash=item19dcda36e9

Well, it's funny you mention about the SD card slot going kaputt - because that's exactly what I think the problem is, but I've got no way of testing it or repairing it (any anyway, it's still well within the Amazon 30-day warranty so it's just of sending it back and getting a new board - but that whole process could take at least 2 or 3 weeks I guess).

I remember reading somewhere (on this or another form, not sure) that the little micro-switches right at the back and underneath of the SD card slot are prone to malfunction. So if the SBC detects no card present, it of course won't boot.

You plug in a usb cable between the OTG and your PC's USB port...


But you are referring to that PC being of the Linux variety I think. Are the sunxi tools available for Windows? Is it possible to take Uboot/script.bin/kernel from a distro on my SD card via Paragon Extfs, copy them to the desktop and send them to the Pi? I suppose that would have to be via PuTTY and the J11 using the aforementioned cable.

Post Last Edited by roses2at at 2014-9-17 09:22

Reply 14# sashijoseph


  
http://www.ebay.co.uk/itm/USB-to ... hash=item19dcda36e9

Errr, but this is not the OTG to USB cable you referred to - it's the USB-TTL-J11 we talked about a few posts ago (and I notice it doesn't come with cables, there are just 4 prongs and you're expected to supply your own wires - I think I'll stick with the one I already ordered as per the Amazon link I gave and which is already on its way anyway.)

I guess I can just take my USB-micro USB cable which I use for data transfer between my PC and tablet.

Reply 16# roses2at

Yes I was referring to the USB-serial cable(just to point out ebay also,as a source of these cables) but apparently positioned it badly.
And since you've already ordered,let's close the chapter.

Reply 17# sashijoseph


Agreed regarding the cable.
However, these questions are still open:
Are the sunxi tools available for Windows? Is it possible to take Uboot/script.bin/kernel from a distro on my SD card via Paragon Extfs, copy them to the desktop and send them to the Pi?



and
What exactly is the sequence to get into Uboot? ...... Is the output only via a PuTTY terminal or can it be to a screen connected to the Pi?

Post Last Edited by sashijoseph at 2014-9-17 23:13

Well this seems to be uncharted territory for the BananaPi.
I haven't got around to testing any of the following stuff.

The tool required for the job is called "fel" and the source code is available at Lemaker's repository
https://github.com/LeMaker/sunxi-tools.git

With the source I think you could compile it for Windows as well but Linux would be better(easier).   
There is an accompanying script called "usb-boot" which simplifies the process of passing parameters to the FEL binary.

The script.bin and kernel image could be easily extracted from a working distro.

The uBoot binaries would have to be compiled with FEL support and since the Lemaker uBoot sources already come with a FEL-enabled target,this too should be do-able.
Do read the stuff on building uBoot.
http://wiki.lemaker.org/Building_u-boot,_script.bin_and_linux-kernel

So finally you will have to have
1.the "fel" binary compiled from source
2.the usb-boot script for easy handling of the fel tool.
3.the "u-boot-spl.bin" and "u-boot.bin" binaries compiled from source
4.kernel uImage and script.bin from a working distro

Now the items at 3) and 4) have to be loaded at specific addresses which have to be passed to fel/usb-boot
What these addresses are for the BananaPi I'm unsure of but hopefully could be unearthed.

The final bit would be entering USB boot mode...this would be done by pressing the uBoot button and then switching on the BPi and hopefully it would have entered FEL mode.
Then from the PC you would need to execute the usb-boot script or do it manually with the fel tool.

The cable would be a micro-usb to USB cable..your tablet one would be fine.
The output would be on whatever is configured in the script.bin or you could probably use the serial debug port for monitoring.

All the info is available on Sunxi.org...I suggest you give it a read.
http://linux-sunxi.org/FEL/USBBoot

heck I didn't notice your post #12

now this thread seems to be meandering crazily...answers before questions and cables all mixed up and buying suggestions after order's been sealed...
got to retire for the night....

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