Index: bin/cp/utils.c
===================================================================
--- bin/cp/utils.c
+++ bin/cp/utils.c
@@ -349,6 +349,7 @@
 	static struct timespec tspec[2];
 	struct stat ts;
 	int rval, gotstat, islink, fdval;
+	unsigned long tflags;
 
 	rval = 0;
 	fdval = fd != -1;
@@ -396,14 +397,23 @@
 			rval = 1;
 		}
 
-	if (!gotstat || fs->st_flags != ts.st_flags)
+	/* Follow mv(1)'s logic WRT file flags.  See its fastcopy() function.
+	 * Same caveats apply. */
+	if (!gotstat ||
+	    (fs->st_flags & ~UF_ARCHIVE) != (ts.st_flags & ~UF_ARCHIVE)) {
+		tflags = fs->st_flags |
+		    (gotstat ? (ts.st_flags & UF_ARCHIVE) : 0);
 		if (fdval ?
-		    fchflags(fd, fs->st_flags) :
-		    (islink ? lchflags(to.p_path, fs->st_flags) :
-		    chflags(to.p_path, fs->st_flags))) {
-			warn("chflags: %s", to.p_path);
-			rval = 1;
+		    fchflags(fd, tflags) :
+		    (islink ? lchflags(to.p_path, tflags) :
+		    chflags(to.p_path, tflags))) {
+			if (errno != EOPNOTSUPP ||
+			    ((fs->st_flags & ~UF_ARCHIVE) != 0)) {
+				warn("chflags: %s", to.p_path);
+				rval = 1;
+			}
 		}
+	}
 
 	return (rval);
 }