OLPC Firmware q7b28


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Works on XO-4 B1 and later only.

  • properly reset the clock on battery failure or oscillator noise,
    • previously the clock may have contained invalid date and time,
    • a one-time extra quick reboot will be observed following upgrade to Q7B28, while the firmware changes the manufacturing data, because of units in the field that have not yet handled the clock reset flag,
  • reduce the wireless scan time,
    • applicable only when using Open Firmware Ok prompt or scripts,
    • no impact on Linux,
  • enable the Bluetooth test for the 8787 wireless module,
  • improve the reliability of the audio test,
    • use a faster random number generator,
    • further decorrelate left and right signals,
    • power off the audio island between tests,
  • remove a timeout return stack trace seen on serial port when the touchscreen is occluded during startup.
  • add SPI FLASH recovery support (using XO-1.5 as a host),
Download q7b28.rom
Build date time 2013-04-02 23:03:30
Source revision 3635
EC version EC 0.4.04
CForth version 7a0de454
WLAN 8686 version 9.0.7.p2
WLAN 8787 version 14.66.09.p80


Open Firmware

  • 3634 OLPC XO-1.75 XO-4 - rely on the RTC register oscillator stop flag to signal when to reinitialise the data. However, already manufactured laptops do not have the oscillator stop flag in the RTC registers cleared, so detect these by absence of a "cv" tag, and add the tag once the flag has been reset.
  • 3633 OLPC - libertas, reduce the scan time to 30ms per channel for an active scan, and raise it to 110ms per channel for a passive scan, based on a kernel patch provided by Marvell.
  • 3632 OLPC XO-4 - restore bluetooth test, regression introduced in 3593.
  • 3631 OLPC - avoid use of RTC undefined data, by detecting power loss and clearing the RTC count.
    • XO-1 and XO-1.5 (ds1385): clear all the RTC count registers, not only the date.
    • XO-1.75 and XO-4 (ds1338): force the century to 20 like on previous models, check and clear the oscillator stop flag, clear all the RTC count registers, separate the clearing of RTC SRAM from the clearing of RTC count, and fix a regression in 3608 where the wrong register offsets were used.
  • 3630 OLPC XO-1.5 - SPI FLASH recovery tools, add XO-4 CForth-only reflash utility word. (this change is not applicable to the XO-4 build, but included here for relevance to the XO-4 platform),
  • 3629 OLPC XO-1.75 - fix overlap with manufacturing data again, this time it was because components delivered to the image with $add-file were not included in the reserved area check. Rather than move the reserved area check deeper into the mkdropin.fth logic, it was easier to reorder the build so that such components were added early. #12627.
  • 3628 SDHCI - added ext-csd! call-through to slot driver, in case someone needs it.
  • 3627 Tokenizer - added some aliases that are useful for debugging and testing.
  • 3626 EXT2 filesystem - added sb-filetype? to test for yet another incompatible extension.
  • 3625 Audio selftest - trivial refactoring to make interactive testing easier.
  • 3624 ARM - added mp-id@ word to get the processor ID in a multiprocessor.
  • 3623 OLPC XO-4 - improved the reliability of the audio test:
    • Instead of the real random number generator, use a LFSR-based PRNG, with a polynomial that happens to give a good spectrum for acoustic testing with OLPC speakers. In addition to working around a unit-dependent problem with the MMP3's hardware RNG, this also speeds up the test because the LFSR is faster than the hardware RNG.
    • Store 16-bit "random" values in the audio buffer instead of using 32-bit random numbers and hoping that the top and bottom halves are uncorrelated. This seems to give better decorrelation of left and right signals.
    • Hard-reset the audio subsystem by powering off/on the audio island between the acoustic and loopback tests, thus making the loopback test more repeatable.
  • 3622 OLPC XO-1.5 - SPI FLASH recovery tools, add support for XO-4 as target. (this change is not applicable to the XO-4 build, but included here for relevance to the XO-4 platform),
  • 3621 OLPC XO-1.5 - SPI FLASH recovery tools, add new command excavate, for reading the target SPI FLASH and writing to a file, for forensic analysis of a target. (this change is not applicable to the XO-4 build, but included here for relevance to the XO-4 platform),
  • 3620 OLPC XO-4 - touchscreen, remove timeout return stack trace


  • 7a0de45 a fix for compiling on Fedora 18 (which has no effect since we continue to build XO-4 Open Firmware releases on Fedora 14),


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