diff --git a/compiler/cross-boot.lisp b/compiler/cross-boot.lisp
index 59cee20ba..050f9fc40 100644
--- a/compiler/cross-boot.lisp
+++ b/compiler/cross-boot.lisp
@@ -266,7 +266,7 @@
 (alexandria:define-constant sys.int::lambda-list-keywords
     '(&allow-other-keys &aux &body &environment &key &optional &rest &whole sys.int::&closure)
   :test 'equal)
-(defvar sys.int::*features* '(:unicode :little-endian :mezzano :ieee-floating-point :ansi-cl :common-lisp))
+(defvar sys.int::*features* '(:unicode :little-endian :mezzano :ieee-floating-point :ansi-cl :common-lisp :64-bit))
 
 ;; Replicated from system/package.lisp. Needed to define packages in package.lisp
 (in-package :mezzano.internals)
diff --git a/system/cold-start.lisp b/system/cold-start.lisp
index b4ca09747..78200c974 100644
--- a/system/cold-start.lisp
+++ b/system/cold-start.lisp
@@ -266,7 +266,8 @@ structures to exist, and for memory to be allocated, but not much beyond that."
                      :mezzano
                      :ieee-floating-point
                      :ansi-cl
-                     :common-lisp)
+                     :common-lisp
+                     :64-bit)
         *macroexpand-hook* 'funcall
         most-positive-fixnum #.(- (expt 2 (- 64 +n-fixnum-bits+ 1)) 1)
         most-negative-fixnum #.(- (expt 2 (- 64 +n-fixnum-bits+ 1)))