  Current searches for the top squark mostly focus on the decay channels of
$\tilde{t}_1 \rightarrow t \chi_1^0$ or $\tilde{t}_1 \rightarrow b \chi_1^\pm
\rightarrow bW \chi_1^0$, leading to $tt/bbWW+\not\mathrel{E}_T$ final states
for top squark pair production at the LHC. In supersymmetric scenarios with
light gauginos other than the neutralino lightest supersymmetric particle
(LSP), different decay modes of the top squark could be dominant, which
significantly weaken the current top squark search limits at the LHC.
Additionally, new decay modes offer alternative discovery channels for top
squark searches. In this paper, we study the top squark and bottom squark decay
in the Bino-like LSP case with light Wino or Higgsino next-to-LSPs (NLSPs), and
identify cases in which additional decay modes become dominant. We also perform
a collider analysis for top squark pair production with mixed top squark decay
final states of $\tilde{t}_1 \to t {\chi}_2^0 \to th {\chi}_1^0$, $\tilde{t}_1
\to b {\chi}_1^\pm \to bW {\chi}_1^0 $, leading to the
$bbbbjj\ell+\not\mathrel{E}_T$ collider signature. The branching fraction for
such decay varies between 25\% and 50\% for a top squark mass larger than 500
GeV with $M_2=M_1+150$ GeV. At the 14 TeV LHC with 300 ${\rm fb}^{-1}$
integrated luminosity, the top squark can be excluded up to about 1040 GeV at
the 95\% C.L., or be discovered up to 940 GeV at 5$\sigma$ significance.
