diff --git a/src/linalg/factorizations.jl b/src/linalg/factorizations.jl
index 347754f..003711a 100644
--- a/src/linalg/factorizations.jl
+++ b/src/linalg/factorizations.jl
@@ -7,10 +7,18 @@ import MatrixAlgebraKit as MAK
 
 const BlockBlasMat{T <: MAK.BlasFloat} = BlockMatrix{T}
 
+function MatrixAlgebraKit.zero!(A::BlockBlasMat)
+    for bj in blockaxes(A, 2), bi in blockaxes(A, 1)
+        a = view(A, bi, bj)
+        MAK.zero!(a)
+    end
+    return A
+end
+
 function MatrixAlgebraKit.one!(A::BlockBlasMat)
-    _one, _zero = one(eltype(A)), zero(eltype(A))
-    @inbounds for j in axes(A, 2), i in axes(A, 1)
-        A[i, j] = ifelse(i == j, _one, _zero)
+    for bj in blockaxes(A, 2), bi in blockaxes(A, 1)
+        a = view(A, bi, bj)
+        bi == bj ? MAK.one!(a) : MAK.zero!(a)
     end
     return A
 end
diff --git a/src/tensors/blocktensor.jl b/src/tensors/blocktensor.jl
index 8fb6258..962f6ce 100644
--- a/src/tensors/blocktensor.jl
+++ b/src/tensors/blocktensor.jl
@@ -123,10 +123,10 @@ end
 # ------------------------
 for (fname, felt) in ((:zeros, :zero), (:ones, :one))
     @eval begin
-        function Base.$fname(::Type{T}, V::TensorMapSumSpace) where {T}
-            TT = blocktensormaptype(spacetype(V), numout(V), numin(V), T)
+        function Base.$fname(::Type{TorA}, V::TensorMapSumSpace) where {TorA}
+            TT = blocktensormaptype(spacetype(V), numout(V), numin(V), TorA)
             t = TT(undef, V)
-            fill!(t, $felt(T))
+            fill!(t, $felt(scalartype(t)))
             return t
         end
     end
@@ -136,9 +136,9 @@ for randfun in (:rand, :randn, :randexp)
     randfun! = Symbol(randfun, :!)
     @eval begin
         function Random.$randfun(
-                rng::Random.AbstractRNG, ::Type{T}, V::TensorMapSumSpace
-            ) where {T}
-            TT = blocktensormaptype(spacetype(V), numout(V), numin(V), T)
+                rng::Random.AbstractRNG, ::Type{TorA}, V::TensorMapSumSpace
+            ) where {TorA}
+            TT = blocktensormaptype(spacetype(V), numout(V), numin(V), TorA)
             t = TT(undef, V)
             Random.$randfun!(rng, t)
             return t