Outside the UK/USA people pronounce acronym EFI (Extensible Firmware Interface) in two different versions: [ɪfɪ] and [ɪ-ef-aɪ].
The first argue their pronunciation that 'I', for example, mean 'Interface' ([ˈɪntəfeɪs]) and should be read as [ɪ]. The second argue that the English letter 'I' is read as [aɪ].
From the point of native English speakers, what variant is more correct?
I hope there are some rules for it and this question is not opinion-based.