v1.5.0a21

• "GPS lost" now says WHY when the receiver is actually fine. A u-blox that
  is receiving but below its own fix-quality gate (few satellites, poor sky
  view -- e.g. indoors) used to show a bare "GPS LOST", identically to a dead
  cable. The driver now reports its live signal quality, the red banner reads
  e.g. "GPS: signal too weak: 4 sats, ±33 m (below receiver quality gate) —
  acquiring", and the HUD shows "ACQ 4" instead of "LOST" while satellites are
  being tracked. First shipped slice of the device-error-visibility work (#142).

• serial0 is now findable in the port menu. The stable on-board-UART alias
  was listed with only its resolved target's name, so /dev/serial0 rendered as
  a second "ttyAMA0" entry -- anyone looking for "serial0" concluded it wasn't
  there. Alias entries now lead with their own name: serial0 (ttyAMA0) - on-board UART (stable).