diff --git a/codeGenCpu6502/src/prog8/codegen/cpu6502/assignment/AssignmentAsmGen.kt b/codeGenCpu6502/src/prog8/codegen/cpu6502/assignment/AssignmentAsmGen.kt
index af0b418c5..96a8ae60e 100644
--- a/codeGenCpu6502/src/prog8/codegen/cpu6502/assignment/AssignmentAsmGen.kt
+++ b/codeGenCpu6502/src/prog8/codegen/cpu6502/assignment/AssignmentAsmGen.kt
@@ -975,8 +975,8 @@ internal class AssignmentAsmGen(private val program: Program,
                         // byte to byte, just assign
                         assignExpressionToRegister(value, target.register!!, targetDt==DataType.BYTE || targetDt==DataType.WORD)
                     } else if(valueDt in ByteDatatypes && targetDt in WordDatatypes) {
-                        // byte to word, assign and zero the msb
-                        TODO("cast byte to word: $value")
+                        // byte to word, just assign
+                        assignExpressionToRegister(value, target.register!!, targetDt==DataType.WORD)
                     }
                     else
                         throw AssemblyError("can't cast $valueDt to $targetDt, this should have been checked in the astchecker")
diff --git a/docs/source/todo.rst b/docs/source/todo.rst
index 6d8c92413..499a55bd8 100644
--- a/docs/source/todo.rst
+++ b/docs/source/todo.rst
@@ -4,7 +4,6 @@ TODO
 For next release
 ^^^^^^^^^^^^^^^^
 - vm: implement remaining sin/cos functions in virtual/math.p8 and merge tables
-- fix "can't cast BYTE to UWORD this should have been checked in the astchecker" crash
 
 ...
 
diff --git a/examples/cx16/sincos.p8 b/examples/cx16/sincos.p8
index c29dd4537..92ea4d1d6 100644
--- a/examples/cx16/sincos.p8
+++ b/examples/cx16/sincos.p8
@@ -47,9 +47,9 @@ main {
 
         for pixelxb in 0 to 255 {
             pixelys = math.cos8(pixelxb) / 2
-            graphics.plot(pixelxb, pixelys+90 as ubyte as uword)      ; TODO fix weird cast error
+            graphics.plot(pixelxb, pixelys+90 as uword)
             pixelys = math.sin8(pixelxb) / 2
-            graphics.plot(pixelxb, pixelys+90 as ubyte as uword)      ; TODO fix weird cast error
+            graphics.plot(pixelxb, pixelys+90 as uword)
         }
     }
 
@@ -69,9 +69,9 @@ main {
 
         for pixelxb in 0 to 179 {
             pixelys = math.cosr8(pixelxb) / 2
-            graphics.plot(pixelxb, pixelys+90 as ubyte as uword)    ; TODO fix weird cast error
+            graphics.plot(pixelxb, pixelys+90 as uword)
             pixelys = math.sinr8(pixelxb) / 2
-            graphics.plot(pixelxb, pixelys+90 as ubyte as uword)    ; TODO fix weird cast error
+            graphics.plot(pixelxb, pixelys+90 as uword)
         }
     }