  We report updates to an ongoing lattice-QCD calculation of the form factors
for the semileptonic decays $B \to \pi \ell \nu$, $B_s \to K \ell \nu$, $B \to
\pi \ell^+ \ell^-$, and $B \to K \ell^+ \ell^-$. The tree-level decays $B_{(s)}
\to \pi (K) \ell \nu$ enable precise determinations of the CKM matrix element
$|V_{ub}|$, while the flavor-changing neutral-current interactions $B \to \pi
(K) \ell^+ \ell^-$ are sensitive to contributions from new physics. This work
uses MILC's (2+1+1)-flavor HISQ ensembles at approximate lattice spacings
between $0.057$ and $0.15$ fm, with physical sea-quark masses on four out of
the seven ensembles. The valence sector is comprised of a clover $b$ quark (in
the Fermilab interpretation) and HISQ light and $s$ quarks. We present
preliminary results for the form factors $f_0$, $f_+$, and $f_T$, including
studies of systematic errors.
