diff --git a/src/basic/engine_variables/fetch_variable_arr.s b/src/basic/engine_variables/fetch_variable_arr.s
index 61271f6a..b2952ecf 100644
--- a/src/basic/engine_variables/fetch_variable_arr.s
+++ b/src/basic/engine_variables/fetch_variable_arr.s
@@ -53,15 +53,17 @@ fetch_variable_arr_check_dimensions:
 
 #if CONFIG_MEMORY_MODEL_60K
 	
-	// XXX!
-	// XXX
-	// XXX
+	phx_trash_a
+	ldx #<VARPNT
+	ldy #$04
+	jsr peek_under_roms
+	sta INDEX+5
+	plx_trash_a
+	cpx INDEX+5
 
 #elif CONFIG_MEMORY_MODEL_46K || CONFIG_MEMORY_MODEL_50K
 
-	// XXX!
-	// XXX
-	// XXX
+	jsr helper_array_check_no_dims
 
 #else // CONFIG_MEMORY_MODEL_38
 
diff --git a/src/basic/engine_variables/helper_array_check_no_dims_46K_50K.s b/src/basic/engine_variables/helper_array_check_no_dims_46K_50K.s
new file mode 100644
index 00000000..f0f96ed8
--- /dev/null
+++ b/src/basic/engine_variables/helper_array_check_no_dims_46K_50K.s
@@ -0,0 +1,26 @@
+// #LAYOUT# STD *       #TAKE-HIGH
+// #LAYOUT# *   BASIC_0 #TAKE-HIGH
+// #LAYOUT# *   *       #IGNORE
+
+// This has to go $E000 or above - routine below banks out the main BASIC ROM!
+
+#if CONFIG_MEMORY_MODEL_46K || CONFIG_MEMORY_MODEL_50K
+
+helper_array_check_no_dims:
+
+	// Unmap BASIC lower ROM
+
+	lda #$26
+	sta CPU_R6510
+
+	// Check number of dimensions
+
+	ldy #$04
+	txa
+	cmp (VARPNT), y
+
+	// Restore default memory mapping
+
+	jmp remap_BASIC_preserve_P
+
+#endif