XO 1.75 11089 Fix: Difference between revisions
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# [[Disassembly_top|Disassemble the laptop]] to access the motherboard. The display does not need to be disconnected; it can be moved slightly out of the way to access the back panel screws. The heat spreader does not have to be removed. |
# [[Disassembly_top|Disassemble the laptop]] to access the motherboard. The display does not need to be disconnected; it can be moved slightly out of the way to access the back panel screws. The heat spreader does not have to be removed. |
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# Plug in the white end of the serial cable, see [[#Finding_the_Serial_Port|below]] for where it goes, |
# Plug in the white end of the serial cable, see [[#Finding_the_Serial_Port|below]] for where it goes, |
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# Plug in a USB drive with Q4B06 or later, |
# Plug in a USB drive with [http://dev.laptop.org/pub/firmware/q4b06/ Q4B06] or later, |
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# Attach the black end of the serial cable to a [[Serial_adapters|serial adapter]], |
# Attach the black end of the serial cable to a [[Serial_adapters|serial adapter]], |
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# Attach the serial adapter to another computer, |
# Attach the serial adapter to another computer, |
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Revision as of 17:34, 14 August 2011
This page is monitored by the OLPC team.
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):
- Turn off the laptop, unplug the power cable, and remove the battery,
- Disassemble the laptop to access the motherboard. The display does not need to be disconnected; it can be moved slightly out of the way to access the back panel screws. The heat spreader does not have to be removed.
- Plug in the white end of the serial cable, see below for where it goes,
- Plug in a USB drive with Q4B06 or later,
- Attach the black end of the serial cable to a serial adapter,
- Attach the serial adapter to another computer,
- Insert the battery,
- Plug the power cable back in, (use only the provided power adapter, not an older one),
- Configure a terminal emulator,
- Power on the laptop. It should print out a boot sequence over the serial port, which will be shown by the terminal emulator. The sequence should end 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.
- Type "dir u:" in the terminal emulator to initialize the USB stack.
- Type "flash u:\q4b06.rom" in the terminal emulator and the laptop will rewrite the firmware and reboot.
- Turn off the laptop, remove the serial cable (if it is no longer required), and reassemble.
Finding the Serial Port
You will need an XO serial adapter designed for use with XOs. The serial port to use is UART3 (CN8). There is a chart showing the location, and this photo:
