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"Breaking into" uboot

Added by Jordi Perez Serra over 6 years ago

Hello, I have a MityDSP L138 and I am trying to gain access to u-boot. I have a NULL modem serial cable which was supplied with the MityDSP kit connected to my pc. The other end is connected to the adapter which was also supplied with the kit and plugged into the J502 connector on the board. I have also checked my connection settings according to this FAQ. https://support.criticallink.com/redmine/projects/arm9-platforms/wiki/Misc_FAQs

From what I understand I should receive data when the board boots up and will have an opportunity to interact before uboot boots into Linux? At the moment I get nothing.

Background:
I tried to update some software on the Linux filesystem and now it will no longer boot, or at least respond to ping or let me ssh in. My idea was that I can use u-boot to boot from mmc or something and fix the Linux filesystem that way.

Thank you for any help.


Replies (5)

RE: "Breaking into" uboot - Added by Jonathan Cormier over 6 years ago

You should see printout similar to this:

OMAP-L138/AM-1808/AM-1810 initialization passed!
Configuring 128MB mDDR
                      Booting TI User Boot Loader
        UBL Version: 1.65:2.28.1 BuiltJul 11 2011 12:49:53
        UBL Flashtype: SPI
Starting SPI Memory Copy...
Valid magicnum, 0x55424CBB, found at offset 0x00010000.
   DONE
Jumping to entry point at 0xC1080000.

U-Boot 2009.11 (Mar 31 2011 - 19:39:18)

I2C:   ready
DRAM:  128 MB
NAND:  256 MiB
MMC:   davinci: 0
In:    serial
Out:   serial
Err:   serial
ARM    Clock : 300000000 Hz
DDR    Clock : 150000000 Hz
EMIFA  CLock : 100000000 Hz
DSP    Clock : 300000000 Hz
ASYNC3 Clock : 150000000 Hz
Enet  config : 2
MMC 0 Enable : 1
Resetting ethernet phy
Net:   Ethernet PHY: GENERIC @ 0x03 [0x8]

Hit any key to stop autoboot:  

RE: "Breaking into" uboot - Added by Jonathan Cormier over 6 years ago

  From what I understand I should receive data when the board boots up and will have an opportunity to interact before uboot boots into Linux? At the moment I get nothing.

This is correct. If the serial port is hooked up you should see u-boot print some information and then if you don't press any key linux will start booting and print out over this terminal.

How did you try to update your filesystem? Replacing files or flashing a new filesystem?

RE: "Breaking into" uboot - Added by Jonathan Cormier over 6 years ago

Also to ask the simple questions, have you tried with and without the null modem? I've run into serial cables that already did the null modem part so the adapter was not necessary.

RE: "Breaking into" uboot - Added by Bob Duke over 6 years ago

Hello Jordi,

Can you confirm that the serial cable provided with the dev kit has the words "Null Modem" printed on each connector?

-Bob

RE: "Breaking into" uboot - Added by Jordi Perez Serra over 6 years ago

Hello,
Thank you very much for your replies. I tried a different cable and it worked.

I attempted to update Linux filesystem by sshing in, changing the opkg feeds to an up to date repository and running opkg update. I see now that there is documentation on the wiki about flashing the NAND. I'm going to go and read that now.

Thanks again or your help.

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