Harmony Link: How to access the serial console (tutorial inside) - AVS Forum
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post #1 of 1 Old 01-12-2013, 02:56 AM - Thread Starter
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Hi everybody,

I've been tinkering with my harmony link and found a way to access the serial console of the harmony link. It's running linux, unfortunaltey there's (yet) no root-shell on login you just can get to the bootloader (redboot).

I also have to ask an favour, by accident I deleted the bootscript mounting the flash memory for start of the linux system, if anybody tries the serial-console access I'd be more than grateful for a screenshot as the command with the corresponding memory adresses shows up right on boot.
So here is how you do it

be sure you're comfortable with voiding your warranty, I'm in no way responsible if you damage your device/yourself. Remember to unplug the harmony link from mains while soldering

Have a look at this pic (warning, high res) for the wiring: http://i.imgur.com/H4Xvn.jpg, Rx and Tx of the 3.3Volts serial converter connected to the solder pads marked in the picture. These pads are on the bottom side of the pcb. I connected ground of the serial-adapter to the 'housing' of the mini-usb plug, it's important to connect ground, otherwise the serial communication won't work. I assume one of the other two remaining solder pads is ground too but I didn't bother to solder a third cable.

After soldering the cables connect the serial adapter to your computer and the harmony link and use a program like putty (for windows) or gtkterm (for linux) to open up the serial interface, probably something like COM4 for windows or /dev/ttyUSB0 for linux. baud rate ist 115200, parity 1, stopbits 8. power up the harmony link and watch the terminal window, you should see the bootloader (redboot) displaying stuff about the hardware etc.

At one point in the boot process the console will say something like "Press ^C within 3 seconds to interrupt bootup ", so press CTRL and C on your keyboard. You'll be dropped to a shell stating "Redboot\>" type help and press enter to get a basic set of commands. Thats about all for now, again, I'd be really happy if anybody could provide me with a screenshot or a copy-and-paste of the console output so I can get my Harmony Link working again The command I'm looking for starts with "ubi attach" followed by hex-locations (eg 0x08800448)

regards, max
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