diff --git a/scheme/ikarus.boot.prebuilt b/scheme/ikarus.boot.prebuilt
index 307df95..16337a0 100644
Binary files a/scheme/ikarus.boot.prebuilt and b/scheme/ikarus.boot.prebuilt differ
diff --git a/scheme/ikarus.compiler.altcogen.ss b/scheme/ikarus.compiler.altcogen.ss
index f086840..b3306e2 100644
--- a/scheme/ikarus.compiler.altcogen.ss
+++ b/scheme/ikarus.compiler.altcogen.ss
@@ -487,7 +487,7 @@
   (define (alloc-check size)
     (E (make-shortcut
          (make-conditional ;;; PCB ALLOC-REDLINE
-           (make-primcall '<= 
+           (make-primcall 'u<= 
              (list (make-primcall 'int+ (list apr size)) 
                    (make-primcall 'mref 
                      (list pcr 
diff --git a/scheme/last-revision b/scheme/last-revision
index 84abd85..d310a7d 100644
--- a/scheme/last-revision
+++ b/scheme/last-revision
@@ -1 +1 @@
-1487
+1488