FC Tourmaline firmware differs from Magnetite in two principal ways when it
comes to Mot C139 target support:

* C139 LCD support is implemented in a more forward-looking manner: instead of
  emulating TI's C-Sample at the lowest R2D driver level and therefore being
  forever limited to 84x48 pixel display size, Tourmaline implements a new
  96x64 pixel framebuffer, matching the native LCD size of C1xx phones.  The UI
  configuration is still black&white only though - the Mother of FreeCalypso
  has no current plans to support color UI on smaller LCD sizes than TI's
  original 176x220 pix.

* Our aftermarket FFS configuration has been changed from 64x3 at 0x3C0000 to
  64x7 at 0x300000.  Our earlier 64x3 config was chosen back in 2015, at that
  time we didn't know how much room we would end up needing for the firmware
  image vs. how much FFS content we would eventually have, and this 64x3 config
  is now deemed to be too small, allowing only one 64 KiB sector for FFS
  content.  Our new FC Tourmaline aftermarket FFS config supports up to 320 KiB
  of FFS content, matches what we use on other platforms with 4 MiB flash chips,
  leaves 3 MiB for the firmware image (our current smallbw UI fw is only 2 MiB),
  and still avoids intersection with Motorola's (or rather Compal's) original
  FFS, which is important for avoiding problems in converting C139 phones back
  and forth between Motorola and FreeCalypso firmwares.