\version "2.18.2"

halve-half-stems =
\override Stem.before-line-breaking =
  #(lambda (grob)
    (if (= 1 (ly:grob-property grob 'duration-log))
      (if (= DOWN (ly:grob-property grob 'direction))
        (and
          (ly:grob-set-property! grob 'stem-begin-position
            (- (ly:grob-property grob 'stem-begin-position)
              (/ (ly:grob-property grob 'length) 2)
            )
          )
          (ly:grob-set-property! grob 'length
            (/ (ly:grob-property grob 'length) 2)
          )
        )
        (ly:grob-set-property! grob 'length
          (/ (ly:grob-property grob 'length) 2)
        )
      )
    )
  )

\new TabStaff \with {
  stringTunings = #ukulele-tuning
  \tabFullNotation
  \stemUp
  \halve-half-stems
}
  \relative c' {
  \partial 2.. a'8 a4 a2 |
  a1 |
  \stemDown
  \partial 2.. g8\4 g4\4 g2\4 |
  g1\4 |
}
\new TabStaff \with {
  stringTunings = #ukulele-tuning
  \tabFullNotation
  \revert Stem.stencil
  \revert Stem.X-extent
  \stemUp
  \halve-half-stems
}
  \relative c' {
  \partial 2.. a'8 a4 a2 |
  a1 |
  \stemDown
  \partial 2.. g8\4 g4\4 g2\4 |
  g1\4 |
}