Probability density of cosmic birefringence for every fifth Gibbs iteration of the BEYONDPLANCK LFI maps. This is analyzed jointly with the Planck PR4 HFI detector split maps. One birefringence angle is additionally sampled for the LFI channels and another for the HFI channels. The error bars include both statistical and systematic uncertainties from LFI. The dashed vertical line shows β = 0°, and the dotted line shows β = 0.34°.