diff --git a/src/banded/BandedLU.jl b/src/banded/BandedLU.jl
index 07f9aeb7..6dfafa00 100644
--- a/src/banded/BandedLU.jl
+++ b/src/banded/BandedLU.jl
@@ -79,9 +79,11 @@ checksquare(A::BandedLU) = (A.m == size(A.data, 2) ||
 # Returns the narrowest blas type given the eltypes of A and b in A*x=b
 function _promote_to_blas_type(::Type{T}, ::Type{S}) where {T<:Number, S<:Number}
     TS = Base.promote_op(/, T, S)
-    # promote to narrowest type
-    TS <: Complex       && return Base.promote_op(/, TS, ComplexF32)
-    TS <: AbstractFloat && return Base.promote_op(/, TS, Float32)
+    if TS ≠ Union{}
+        # promote to narrowest type
+        TS <: Complex       && return Base.promote_op(/, TS, ComplexF32)
+        TS <: AbstractFloat && return Base.promote_op(/, TS, Float32)
+    end
     error("Cannot convert objects of element type $(T), $(S) to a `BlasFloat` type")
 end
 
diff --git a/test/test_bandedlu.jl b/test/test_bandedlu.jl
index 34151a4e..5fe7e8ea 100644
--- a/test/test_bandedlu.jl
+++ b/test/test_bandedlu.jl
@@ -31,7 +31,6 @@ cldiv!(A, b) = ldiv!(adjoint(A), b)
         @test BandedMatrices._promote_to_blas_type(typ, Int16)      == typ
         @test BandedMatrices._promote_to_blas_type(typ, Int8)       == typ
 
-
         @test_throws ErrorException BandedMatrices._promote_to_blas_type(_foo, Float64)
     end
 
diff --git a/test/test_broadcasting.jl b/test/test_broadcasting.jl
index 0b38ae0b..39ef6f15 100644
--- a/test/test_broadcasting.jl
+++ b/test/test_broadcasting.jl
@@ -141,11 +141,17 @@ using BandedMatrices, LinearAlgebra, LazyArrays, Test
         A = brand(5,5,1,1)
         A.data .= NaN
         lmul!(0.0,A)
+        @test isnan(norm(A)) == isnan(norm(lmul!(0.0,[NaN])))
+
+        lmul!(false,A)
         @test norm(A) == 0.0
 
         A = brand(5,5,1,1)
         A.data .= NaN
         rmul!(A,0.0)
+        @test isnan(norm(A)) == isnan(norm(rmul!([NaN],0.0)))
+
+        rmul!(A,false)
         @test norm(A) == 0.0
 
         n = 100