diff --git a/README.md b/README.md
index 34c4172..a605ac9 100644
--- a/README.md
+++ b/README.md
@@ -20,6 +20,7 @@ There are some basic examples in `osc-examples.lisp` and the `devices/examples/o
   - will raise an exception if input is malformed
   - no pattern matching on addresses
   - float en/decoding only tested on sbcl, cmucl, openmcl and allegro
+  - the `devices` module only works on sbcl
   - only supports the type(tag)s specified in the OSC spec
 
 ## things to do in :osc
diff --git a/osc-time.lisp b/osc-time.lisp
index ae75b24..ffc69ad 100644
--- a/osc-time.lisp
+++ b/osc-time.lisp
@@ -65,7 +65,7 @@ with microsecond precision, relative to 19700101."
   (coerce (/ usecs  +usecs+) 'double-float))
 
 (defun subsecs->microseconds (subsecs)
-  (declare (type (float 0 1) subsecs))
+  (declare (type (float 0.0 1.0) subsecs))
   (round (* subsecs +usecs+)))
 
 (defun int32->subsecs (int32)
diff --git a/osc.asd b/osc.asd
index af804fa..22d72fc 100644
--- a/osc.asd
+++ b/osc.asd
@@ -17,6 +17,7 @@
    (:file "osc-tests" :depends-on ("osc"))
    (:file "package")
    (:module "devices"
+    :if-feature :sbcl
     :depends-on ("package" "osc-data")
     :components
             ((:file "socket-functions")