Index: fw/sdk/yc_ipc.c
===================================================================
--- /YC3121_SDK/fw/sdk/yc_ipc.c	(revision 828)
+++ /YC3121_SDK/fw/sdk/yc_ipc.c	(working copy)
@@ -33,7 +33,7 @@
     }
     else
     {
-        retLen = ((ipcendaddr - ipcstartaddr + 1) - (readtx - wrtptr));
+        retLen = ((ipcendaddr - ipcstartaddr + 1) - (wrtptr - readtx));
     }
     if(bt_lpm_mode==1)
     {