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−As of this writing (2017-05-01), there is an unexplained hardware problem on
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−some of our FCDEV3B boards in that flashed firmware images which use flash boot
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−mode 1 (see the Flash-boot-modes article) fail to boot.  It is not currently
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−known how many boards are affected by this problem; it is possible that the
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−Mother's S/N 001 board is the only one that exhibits this oddity.
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−
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−This problem particularly affects our FC Magnetite firmware, as the latter uses
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−flash boot mode 1 just like TI's TCS211 fw from which it originates.  OTOH, our
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−FC Citrine firmware, which uses flash boot mode 0, boots just fine.  A minimal
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−test case has been created under target-utils/flash-boot-test in this
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−repository: it is a simple loadagent-like standalone application that is built
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−to be booted from flash instead of expecting to be loaded serially, and it is
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−built in two versions, one for mode 0 and another for mode 1.  Both versions
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−work on an Openmoko-made GTA02 (the mode 1 version continuously reboots every
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−few seconds because it doesn't disable the watchdog timer, but it is still very
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−clearly alive) as well as on those FCDEV3B boards which aren't affected, but on
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−FCDEV3B S/N 001 the mode 1 version fails to boot just like the full Magnetite
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−firmware.
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−
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−The Mother of FreeCalypso does not currently have any prognosis as to when or
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−even if the mysterious hardware problem that causes flash boot mode 1 to fail
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−can be fixed.  Logical reasoning tells us that it must be a hardware problem,
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−as the flash boot mode in question works without a hitch on every pre-existing
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−Calypso device known to us, and similar logical reasoning tells us that the
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−watchdog timer probably has to be involved in some way, as it is the mechanism
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−underlying flash boot mode 1 (again, see the Flash-boot-modes article), but I
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−am at a total loss when it comes to what kind of board-level problem could
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−possibly produce such behaviour.  But then if only the S/N 001 board is affected
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−and no others, it could just be a defective chip.  More data points need to be
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−gathered before we shall know whether or not we have a real problem.
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−
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−For those who do have a flash-boot-challenged FCDEV3B board, two workarounds
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−have been developed, in this chronological order:
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−
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−1. One can boot the board in the serial download mode, and download a
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−   teensy-tiny piece of code that disables the boot ROM and jumps to address 0.
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−   If the flash contains a firmware image meant to be booted in mode 1, this
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−   image will get indirectly booted in this manner.  Run a command like this:
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−
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−fc-iram -h fcfam /dev/ttyXXX /opt/freecalypso/target-bin/flash-boot-wa.srec rvinterf
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−
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−(fc-iram has been extended to support second program invokation just like
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− fc-xram, just for this peculiar use case.  The flash-boot-wa.srec helper can
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− also be booted via fc-xram.)
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−
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−2. After doing the above, I found a way to patch the Magnetite firmware image
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−   to boot in mode 0 - see the Flash-boot-mode-hack write-up in the Magnetite
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−   source tree.  With this patch applied, FC Magnetite happily boots directly
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−   from flash on my board without needing fc-iram or fc-xram assistance.