  We prove an identity relating Mahler measures of a certain family of
non-tempered polynomials to those of tempered polynomials. Evaluations of
Mahler measures of some polynomials in the first family are also given in terms
of special values of $L$-functions and logarithms. Finally, we prove Boyd's
conjectures for conductor $30$ elliptic curves using our new identity,
Brunault-Mellit-Zudilin's formula and additional functional identities for
Mahler measures.
