diff --git a/sbp.cabal b/sbp.cabal
--- a/sbp.cabal
+++ b/sbp.cabal
@@ -1,5 +1,5 @@
 name:                  sbp
-version:               0.50.5
+version:               0.50.6
 synopsis:              SwiftNav's SBP Library
 homepage:              https://github.com/swift-nav/libsbp
 license:               LGPL-3
diff --git a/src/SwiftNav/SBP.hs b/src/SwiftNav/SBP.hs
--- a/src/SwiftNav/SBP.hs
+++ b/src/SwiftNav/SBP.hs
@@ -133,6 +133,7 @@
    | SBPMsgUartState MsgUartState Msg
    | SBPMsgVelEcef MsgVelEcef Msg
    | SBPMsgVelNed MsgVelNed Msg
+   | SBPMsgBadCrc Msg
    | SBPMsgUnknown Msg
   deriving ( Show, Read, Eq )
 
@@ -141,76 +142,76 @@
     preamble <- getWord8
     if preamble /= msgSBPPreamble then get else do
       sbp <- get
-      if checkCrc sbp /= msgSBPCrc sbp then get else
-        return $ decode' sbp where
-          decode' sbp
-            | msgSBPType sbp == msgAcqResult = SBPMsgAcqResult (decode (fromStrict (msgSBPPayload sbp))) sbp
-            | msgSBPType sbp == msgAcqResultDepA = SBPMsgAcqResultDepA (decode (fromStrict (msgSBPPayload sbp))) sbp
-            | msgSBPType sbp == msgAlmanac = SBPMsgAlmanac (decode (fromStrict (msgSBPPayload sbp))) sbp
-            | msgSBPType sbp == msgBasePos = SBPMsgBasePos (decode (fromStrict (msgSBPPayload sbp))) sbp
-            | msgSBPType sbp == msgBaselineEcef = SBPMsgBaselineEcef (decode (fromStrict (msgSBPPayload sbp))) sbp
-            | msgSBPType sbp == msgBaselineNed = SBPMsgBaselineNed (decode (fromStrict (msgSBPPayload sbp))) sbp
-            | msgSBPType sbp == msgBootloaderHandshakeDepA = SBPMsgBootloaderHandshakeDepA (decode (fromStrict (msgSBPPayload sbp))) sbp
-            | msgSBPType sbp == msgBootloaderHandshakeReq = SBPMsgBootloaderHandshakeReq (decode (fromStrict (msgSBPPayload sbp))) sbp
-            | msgSBPType sbp == msgBootloaderHandshakeResp = SBPMsgBootloaderHandshakeResp (decode (fromStrict (msgSBPPayload sbp))) sbp
-            | msgSBPType sbp == msgBootloaderJumpToApp = SBPMsgBootloaderJumpToApp (decode (fromStrict (msgSBPPayload sbp))) sbp
-            | msgSBPType sbp == msgCwResults = SBPMsgCwResults (decode (fromStrict (msgSBPPayload sbp))) sbp
-            | msgSBPType sbp == msgCwStart = SBPMsgCwStart (decode (fromStrict (msgSBPPayload sbp))) sbp
-            | msgSBPType sbp == msgDops = SBPMsgDops (decode (fromStrict (msgSBPPayload sbp))) sbp
-            | msgSBPType sbp == msgEphemeris = SBPMsgEphemeris (decode (fromStrict (msgSBPPayload sbp))) sbp
-            | msgSBPType sbp == msgEphemerisDepA = SBPMsgEphemerisDepA (decode (fromStrict (msgSBPPayload sbp))) sbp
-            | msgSBPType sbp == msgEphemerisDepB = SBPMsgEphemerisDepB (decode (fromStrict (msgSBPPayload sbp))) sbp
-            | msgSBPType sbp == msgExtEvent = SBPMsgExtEvent (decode (fromStrict (msgSBPPayload sbp))) sbp
-            | msgSBPType sbp == msgFileioReadDirReq = SBPMsgFileioReadDirReq (decode (fromStrict (msgSBPPayload sbp))) sbp
-            | msgSBPType sbp == msgFileioReadDirResp = SBPMsgFileioReadDirResp (decode (fromStrict (msgSBPPayload sbp))) sbp
-            | msgSBPType sbp == msgFileioReadReq = SBPMsgFileioReadReq (decode (fromStrict (msgSBPPayload sbp))) sbp
-            | msgSBPType sbp == msgFileioReadResp = SBPMsgFileioReadResp (decode (fromStrict (msgSBPPayload sbp))) sbp
-            | msgSBPType sbp == msgFileioRemove = SBPMsgFileioRemove (decode (fromStrict (msgSBPPayload sbp))) sbp
-            | msgSBPType sbp == msgFileioWriteReq = SBPMsgFileioWriteReq (decode (fromStrict (msgSBPPayload sbp))) sbp
-            | msgSBPType sbp == msgFileioWriteResp = SBPMsgFileioWriteResp (decode (fromStrict (msgSBPPayload sbp))) sbp
-            | msgSBPType sbp == msgFlashDone = SBPMsgFlashDone (decode (fromStrict (msgSBPPayload sbp))) sbp
-            | msgSBPType sbp == msgFlashErase = SBPMsgFlashErase (decode (fromStrict (msgSBPPayload sbp))) sbp
-            | msgSBPType sbp == msgFlashProgram = SBPMsgFlashProgram (decode (fromStrict (msgSBPPayload sbp))) sbp
-            | msgSBPType sbp == msgFlashReadReq = SBPMsgFlashReadReq (decode (fromStrict (msgSBPPayload sbp))) sbp
-            | msgSBPType sbp == msgFlashReadResp = SBPMsgFlashReadResp (decode (fromStrict (msgSBPPayload sbp))) sbp
-            | msgSBPType sbp == msgGpsTime = SBPMsgGpsTime (decode (fromStrict (msgSBPPayload sbp))) sbp
-            | msgSBPType sbp == msgHeartbeat = SBPMsgHeartbeat (decode (fromStrict (msgSBPPayload sbp))) sbp
-            | msgSBPType sbp == msgIarState = SBPMsgIarState (decode (fromStrict (msgSBPPayload sbp))) sbp
-            | msgSBPType sbp == msgInitBase = SBPMsgInitBase (decode (fromStrict (msgSBPPayload sbp))) sbp
-            | msgSBPType sbp == msgLog = SBPMsgLog (decode (fromStrict (msgSBPPayload sbp))) sbp
-            | msgSBPType sbp == msgM25FlashWriteStatus = SBPMsgM25FlashWriteStatus (decode (fromStrict (msgSBPPayload sbp))) sbp
-            | msgSBPType sbp == msgMaskSatellite = SBPMsgMaskSatellite (decode (fromStrict (msgSBPPayload sbp))) sbp
-            | msgSBPType sbp == msgNapDeviceDnaReq = SBPMsgNapDeviceDnaReq (decode (fromStrict (msgSBPPayload sbp))) sbp
-            | msgSBPType sbp == msgNapDeviceDnaResp = SBPMsgNapDeviceDnaResp (decode (fromStrict (msgSBPPayload sbp))) sbp
-            | msgSBPType sbp == msgObs = SBPMsgObs (decode (fromStrict (msgSBPPayload sbp))) sbp
-            | msgSBPType sbp == msgObsDepA = SBPMsgObsDepA (decode (fromStrict (msgSBPPayload sbp))) sbp
-            | msgSBPType sbp == msgPosEcef = SBPMsgPosEcef (decode (fromStrict (msgSBPPayload sbp))) sbp
-            | msgSBPType sbp == msgPosLlh = SBPMsgPosLlh (decode (fromStrict (msgSBPPayload sbp))) sbp
-            | msgSBPType sbp == msgPrintDep = SBPMsgPrintDep (decode (fromStrict (msgSBPPayload sbp))) sbp
-            | msgSBPType sbp == msgReset = SBPMsgReset (decode (fromStrict (msgSBPPayload sbp))) sbp
-            | msgSBPType sbp == msgResetFilters = SBPMsgResetFilters (decode (fromStrict (msgSBPPayload sbp))) sbp
-            | msgSBPType sbp == msgSetTime = SBPMsgSetTime (decode (fromStrict (msgSBPPayload sbp))) sbp
-            | msgSBPType sbp == msgSettingsReadByIndexDone = SBPMsgSettingsReadByIndexDone (decode (fromStrict (msgSBPPayload sbp))) sbp
-            | msgSBPType sbp == msgSettingsReadByIndexReq = SBPMsgSettingsReadByIndexReq (decode (fromStrict (msgSBPPayload sbp))) sbp
-            | msgSBPType sbp == msgSettingsReadByIndexResp = SBPMsgSettingsReadByIndexResp (decode (fromStrict (msgSBPPayload sbp))) sbp
-            | msgSBPType sbp == msgSettingsReadReq = SBPMsgSettingsReadReq (decode (fromStrict (msgSBPPayload sbp))) sbp
-            | msgSBPType sbp == msgSettingsReadResp = SBPMsgSettingsReadResp (decode (fromStrict (msgSBPPayload sbp))) sbp
-            | msgSBPType sbp == msgSettingsSave = SBPMsgSettingsSave (decode (fromStrict (msgSBPPayload sbp))) sbp
-            | msgSBPType sbp == msgSettingsWrite = SBPMsgSettingsWrite (decode (fromStrict (msgSBPPayload sbp))) sbp
-            | msgSBPType sbp == msgStartup = SBPMsgStartup (decode (fromStrict (msgSBPPayload sbp))) sbp
-            | msgSBPType sbp == msgStmFlashLockSector = SBPMsgStmFlashLockSector (decode (fromStrict (msgSBPPayload sbp))) sbp
-            | msgSBPType sbp == msgStmFlashUnlockSector = SBPMsgStmFlashUnlockSector (decode (fromStrict (msgSBPPayload sbp))) sbp
-            | msgSBPType sbp == msgStmUniqueIdReq = SBPMsgStmUniqueIdReq (decode (fromStrict (msgSBPPayload sbp))) sbp
-            | msgSBPType sbp == msgStmUniqueIdResp = SBPMsgStmUniqueIdResp (decode (fromStrict (msgSBPPayload sbp))) sbp
-            | msgSBPType sbp == msgThreadState = SBPMsgThreadState (decode (fromStrict (msgSBPPayload sbp))) sbp
-            | msgSBPType sbp == msgTrackingIq = SBPMsgTrackingIq (decode (fromStrict (msgSBPPayload sbp))) sbp
-            | msgSBPType sbp == msgTrackingState = SBPMsgTrackingState (decode (fromStrict (msgSBPPayload sbp))) sbp
-            | msgSBPType sbp == msgTrackingStateDepA = SBPMsgTrackingStateDepA (decode (fromStrict (msgSBPPayload sbp))) sbp
-            | msgSBPType sbp == msgTweet = SBPMsgTweet (decode (fromStrict (msgSBPPayload sbp))) sbp
-            | msgSBPType sbp == msgUartState = SBPMsgUartState (decode (fromStrict (msgSBPPayload sbp))) sbp
-            | msgSBPType sbp == msgVelEcef = SBPMsgVelEcef (decode (fromStrict (msgSBPPayload sbp))) sbp
-            | msgSBPType sbp == msgVelNed = SBPMsgVelNed (decode (fromStrict (msgSBPPayload sbp))) sbp
-            | otherwise = SBPMsgUnknown sbp
+      return $ decode' sbp where
+        decode' sbp
+          | checkCrc sbp /= msgSBPCrc sbp = SBPMsgBadCrc sbp
+          | msgSBPType sbp == msgAcqResult = SBPMsgAcqResult (decode (fromStrict (msgSBPPayload sbp))) sbp
+          | msgSBPType sbp == msgAcqResultDepA = SBPMsgAcqResultDepA (decode (fromStrict (msgSBPPayload sbp))) sbp
+          | msgSBPType sbp == msgAlmanac = SBPMsgAlmanac (decode (fromStrict (msgSBPPayload sbp))) sbp
+          | msgSBPType sbp == msgBasePos = SBPMsgBasePos (decode (fromStrict (msgSBPPayload sbp))) sbp
+          | msgSBPType sbp == msgBaselineEcef = SBPMsgBaselineEcef (decode (fromStrict (msgSBPPayload sbp))) sbp
+          | msgSBPType sbp == msgBaselineNed = SBPMsgBaselineNed (decode (fromStrict (msgSBPPayload sbp))) sbp
+          | msgSBPType sbp == msgBootloaderHandshakeDepA = SBPMsgBootloaderHandshakeDepA (decode (fromStrict (msgSBPPayload sbp))) sbp
+          | msgSBPType sbp == msgBootloaderHandshakeReq = SBPMsgBootloaderHandshakeReq (decode (fromStrict (msgSBPPayload sbp))) sbp
+          | msgSBPType sbp == msgBootloaderHandshakeResp = SBPMsgBootloaderHandshakeResp (decode (fromStrict (msgSBPPayload sbp))) sbp
+          | msgSBPType sbp == msgBootloaderJumpToApp = SBPMsgBootloaderJumpToApp (decode (fromStrict (msgSBPPayload sbp))) sbp
+          | msgSBPType sbp == msgCwResults = SBPMsgCwResults (decode (fromStrict (msgSBPPayload sbp))) sbp
+          | msgSBPType sbp == msgCwStart = SBPMsgCwStart (decode (fromStrict (msgSBPPayload sbp))) sbp
+          | msgSBPType sbp == msgDops = SBPMsgDops (decode (fromStrict (msgSBPPayload sbp))) sbp
+          | msgSBPType sbp == msgEphemeris = SBPMsgEphemeris (decode (fromStrict (msgSBPPayload sbp))) sbp
+          | msgSBPType sbp == msgEphemerisDepA = SBPMsgEphemerisDepA (decode (fromStrict (msgSBPPayload sbp))) sbp
+          | msgSBPType sbp == msgEphemerisDepB = SBPMsgEphemerisDepB (decode (fromStrict (msgSBPPayload sbp))) sbp
+          | msgSBPType sbp == msgExtEvent = SBPMsgExtEvent (decode (fromStrict (msgSBPPayload sbp))) sbp
+          | msgSBPType sbp == msgFileioReadDirReq = SBPMsgFileioReadDirReq (decode (fromStrict (msgSBPPayload sbp))) sbp
+          | msgSBPType sbp == msgFileioReadDirResp = SBPMsgFileioReadDirResp (decode (fromStrict (msgSBPPayload sbp))) sbp
+          | msgSBPType sbp == msgFileioReadReq = SBPMsgFileioReadReq (decode (fromStrict (msgSBPPayload sbp))) sbp
+          | msgSBPType sbp == msgFileioReadResp = SBPMsgFileioReadResp (decode (fromStrict (msgSBPPayload sbp))) sbp
+          | msgSBPType sbp == msgFileioRemove = SBPMsgFileioRemove (decode (fromStrict (msgSBPPayload sbp))) sbp
+          | msgSBPType sbp == msgFileioWriteReq = SBPMsgFileioWriteReq (decode (fromStrict (msgSBPPayload sbp))) sbp
+          | msgSBPType sbp == msgFileioWriteResp = SBPMsgFileioWriteResp (decode (fromStrict (msgSBPPayload sbp))) sbp
+          | msgSBPType sbp == msgFlashDone = SBPMsgFlashDone (decode (fromStrict (msgSBPPayload sbp))) sbp
+          | msgSBPType sbp == msgFlashErase = SBPMsgFlashErase (decode (fromStrict (msgSBPPayload sbp))) sbp
+          | msgSBPType sbp == msgFlashProgram = SBPMsgFlashProgram (decode (fromStrict (msgSBPPayload sbp))) sbp
+          | msgSBPType sbp == msgFlashReadReq = SBPMsgFlashReadReq (decode (fromStrict (msgSBPPayload sbp))) sbp
+          | msgSBPType sbp == msgFlashReadResp = SBPMsgFlashReadResp (decode (fromStrict (msgSBPPayload sbp))) sbp
+          | msgSBPType sbp == msgGpsTime = SBPMsgGpsTime (decode (fromStrict (msgSBPPayload sbp))) sbp
+          | msgSBPType sbp == msgHeartbeat = SBPMsgHeartbeat (decode (fromStrict (msgSBPPayload sbp))) sbp
+          | msgSBPType sbp == msgIarState = SBPMsgIarState (decode (fromStrict (msgSBPPayload sbp))) sbp
+          | msgSBPType sbp == msgInitBase = SBPMsgInitBase (decode (fromStrict (msgSBPPayload sbp))) sbp
+          | msgSBPType sbp == msgLog = SBPMsgLog (decode (fromStrict (msgSBPPayload sbp))) sbp
+          | msgSBPType sbp == msgM25FlashWriteStatus = SBPMsgM25FlashWriteStatus (decode (fromStrict (msgSBPPayload sbp))) sbp
+          | msgSBPType sbp == msgMaskSatellite = SBPMsgMaskSatellite (decode (fromStrict (msgSBPPayload sbp))) sbp
+          | msgSBPType sbp == msgNapDeviceDnaReq = SBPMsgNapDeviceDnaReq (decode (fromStrict (msgSBPPayload sbp))) sbp
+          | msgSBPType sbp == msgNapDeviceDnaResp = SBPMsgNapDeviceDnaResp (decode (fromStrict (msgSBPPayload sbp))) sbp
+          | msgSBPType sbp == msgObs = SBPMsgObs (decode (fromStrict (msgSBPPayload sbp))) sbp
+          | msgSBPType sbp == msgObsDepA = SBPMsgObsDepA (decode (fromStrict (msgSBPPayload sbp))) sbp
+          | msgSBPType sbp == msgPosEcef = SBPMsgPosEcef (decode (fromStrict (msgSBPPayload sbp))) sbp
+          | msgSBPType sbp == msgPosLlh = SBPMsgPosLlh (decode (fromStrict (msgSBPPayload sbp))) sbp
+          | msgSBPType sbp == msgPrintDep = SBPMsgPrintDep (decode (fromStrict (msgSBPPayload sbp))) sbp
+          | msgSBPType sbp == msgReset = SBPMsgReset (decode (fromStrict (msgSBPPayload sbp))) sbp
+          | msgSBPType sbp == msgResetFilters = SBPMsgResetFilters (decode (fromStrict (msgSBPPayload sbp))) sbp
+          | msgSBPType sbp == msgSetTime = SBPMsgSetTime (decode (fromStrict (msgSBPPayload sbp))) sbp
+          | msgSBPType sbp == msgSettingsReadByIndexDone = SBPMsgSettingsReadByIndexDone (decode (fromStrict (msgSBPPayload sbp))) sbp
+          | msgSBPType sbp == msgSettingsReadByIndexReq = SBPMsgSettingsReadByIndexReq (decode (fromStrict (msgSBPPayload sbp))) sbp
+          | msgSBPType sbp == msgSettingsReadByIndexResp = SBPMsgSettingsReadByIndexResp (decode (fromStrict (msgSBPPayload sbp))) sbp
+          | msgSBPType sbp == msgSettingsReadReq = SBPMsgSettingsReadReq (decode (fromStrict (msgSBPPayload sbp))) sbp
+          | msgSBPType sbp == msgSettingsReadResp = SBPMsgSettingsReadResp (decode (fromStrict (msgSBPPayload sbp))) sbp
+          | msgSBPType sbp == msgSettingsSave = SBPMsgSettingsSave (decode (fromStrict (msgSBPPayload sbp))) sbp
+          | msgSBPType sbp == msgSettingsWrite = SBPMsgSettingsWrite (decode (fromStrict (msgSBPPayload sbp))) sbp
+          | msgSBPType sbp == msgStartup = SBPMsgStartup (decode (fromStrict (msgSBPPayload sbp))) sbp
+          | msgSBPType sbp == msgStmFlashLockSector = SBPMsgStmFlashLockSector (decode (fromStrict (msgSBPPayload sbp))) sbp
+          | msgSBPType sbp == msgStmFlashUnlockSector = SBPMsgStmFlashUnlockSector (decode (fromStrict (msgSBPPayload sbp))) sbp
+          | msgSBPType sbp == msgStmUniqueIdReq = SBPMsgStmUniqueIdReq (decode (fromStrict (msgSBPPayload sbp))) sbp
+          | msgSBPType sbp == msgStmUniqueIdResp = SBPMsgStmUniqueIdResp (decode (fromStrict (msgSBPPayload sbp))) sbp
+          | msgSBPType sbp == msgThreadState = SBPMsgThreadState (decode (fromStrict (msgSBPPayload sbp))) sbp
+          | msgSBPType sbp == msgTrackingIq = SBPMsgTrackingIq (decode (fromStrict (msgSBPPayload sbp))) sbp
+          | msgSBPType sbp == msgTrackingState = SBPMsgTrackingState (decode (fromStrict (msgSBPPayload sbp))) sbp
+          | msgSBPType sbp == msgTrackingStateDepA = SBPMsgTrackingStateDepA (decode (fromStrict (msgSBPPayload sbp))) sbp
+          | msgSBPType sbp == msgTweet = SBPMsgTweet (decode (fromStrict (msgSBPPayload sbp))) sbp
+          | msgSBPType sbp == msgUartState = SBPMsgUartState (decode (fromStrict (msgSBPPayload sbp))) sbp
+          | msgSBPType sbp == msgVelEcef = SBPMsgVelEcef (decode (fromStrict (msgSBPPayload sbp))) sbp
+          | msgSBPType sbp == msgVelNed = SBPMsgVelNed (decode (fromStrict (msgSBPPayload sbp))) sbp
+          | otherwise = SBPMsgUnknown sbp
 
   put msg = do
     putWord8 msgSBPPreamble