biblatex: title won't show up correctly

Question

I use biblatex and biber to include a bibliography based on a .bib-file. I print the title in the bibliography based on the biblatex-instruction \printfield{title}. Unfortunatley, the title shows up incorrectly sometimes. A few examples: - title = {ECU firmware} in the .bib-file results in ECU rmware - title = {Nice temperature of 25°C} results in Nice temperature of 25C

In the biblatex-documentation I found:

\printfield[hformati]{hfieldi}

This command prints a hfieldi using the formatting directive hformati , as defined with \DeclareFieldFormat . ...

So ist the formatting directive for the title field the problem? Can I change it in order to get the expected result?

Here is MWE:

\documentclass{article}

\usepackage[ngerman]{babel}
\usepackage[T1]{fontenc}
\usepackage[utf8]{inputenc}
\usepackage[backend=biber,style=alphabetic]{biblatex}
\usepackage{csquotes}
\usepackage{filecontents}

\begin{filecontents*}{bibfile.bib}
@newtype{xxx,
  title   = {ECU firmware},
  author  = {author1},
}
\end{filecontents*}

\addbibresource{bibfile.bib}

\DeclareBibliographyDriver{newtype}{
    \usebibmacro{begentry}
    \printnames{author}
    \newunit\newblock
    \printfield{title}
    \usebibmacro{finentry}
}

\begin{document}
See~\cite{xxx}

\printbibliography
\end{document}

results in:

Thanks a lot in advance!

Answer 1

Looking into the error messages in the log files, one can find there

! Package inputenc Error: Unicode char fi (U+FB01) (inputenc) not set up for use with LaTeX.

this pretty much already tells the solution. There seems to be a character, which is not suitable as input for the bibliography, more precisely the glyph fi which represents a ligature of f and i. To solve this simply delete the symbol and retype f and i as individual letters.