XO 1.75 11089 Fix

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Revision as of 14:13, 6 August 2011 by Greenfeld (talk | contribs) (May be the first time some people have to use serial adapters)
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Version Q4B05 of Open Firmware for the XO 1.75 B1 laptop had a bug (<trac>11089</trac>) which causes the laptops to boot up with a white screen if it has been ten days since their manufacture, or if the RTC battery is removed. The symptom is a white screen (nothing on it) on boot.

The Fix

Fortunately, the fix to this is simple (yet tedious):

  1. Disassemble the laptop to access the motherboard (the heat spreader does not have to be removed).
  2. Plug in a serial cable (see below), and a USB key with Q4B06 or later.
  3. Attach the serial cable/adapter to another computer, and configure a terminal emulation program on this other computer to access the serial adapter at 115200 baud, 8 bits, No parity, 1 stop bit.
  4. Boot the laptop. It should print out a boot sequence over the serial port, ending in Unrecognized SPI Flash ID. It should then provide an ok prompt. If at this point, it stops somewhere else or doesn't provide a prompt (like after Releasing) you have another problem. Please contact wad.
  5. Type "dir u:" in the terminal program to initialize the USB stack.
  6. Type "flash u:\q4b06.rom". When the laptop finishes reflashing and returns an ok, either reboot (type "bye") or poweroff the laptop.
  7. Reassemble

Finding the Serial Port

You will need an XO serial adapter designed for use with XO 1.5's or higher (which also work with XO-1's). The serial port to use is UART3 (CN8). There is a chart showing the location, and this photo:

1.75 serial connector.png
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