This article re-examines the evidence for the value of the Linear B sign pu₂, in particular its appearance in the term da-pu₂-ri-to- ‘labyrinth’, and demonstrates that it stands specifically for the value /pʰu/ (contrary to the usual assumption that it represents both /pʰu/ and /bu/). It then discusses the further implications of this conclusion, in particular for the interpretation of the undeciphered signs *56 and *22, which are often assigned to the same series as pu₂, as well as any other similar signs which may exist. This discussion illustrates the crucial impact that establishing a single sign’s value may have on the wider understanding of the Linear B script, as well as on its relationship with its parent script Linear A and even the possibility of reconstructing aspects of the Minoan language.