diff --git a/src/CHANGES.md b/src/CHANGES.md
index bc419068..11cd7393 100644
--- a/src/CHANGES.md
+++ b/src/CHANGES.md
@@ -1,5 +1,9 @@
 # Development Changes
 
+## 0.8.153 - 2025-03-05
+* added update warning once 0.9.x should be installed -> not possible using OTA because of changed partition layout
+* improved CMT communication
+
 ## 0.8.152 - 2024-10-07
 * patching MqTT library to prevent raise conditions while using semaphores
 * update ESP32 espressif platform to `0.6.9`
diff --git a/src/defines.h b/src/defines.h
index 1f3d013c..105220cf 100644
--- a/src/defines.h
+++ b/src/defines.h
@@ -13,7 +13,7 @@
 //-------------------------------------
 #define VERSION_MAJOR       0
 #define VERSION_MINOR       8
-#define VERSION_PATCH       152
+#define VERSION_PATCH       153
 //-------------------------------------
 typedef struct {
     uint8_t ch;
diff --git a/src/hms/cmt2300a.h b/src/hms/cmt2300a.h
index 626d3e79..ece6fbc3 100644
--- a/src/hms/cmt2300a.h
+++ b/src/hms/cmt2300a.h
@@ -168,8 +168,13 @@ enum class CmtStatus : uint8_t {
 #define CMT2300A_MASK_PKT_OK_FLG        0x01
 
 class Cmt2300a {
+    private: /*types*/
+        static constexpr uint8_t CmtTimeoutMs = 40;
+
     public:
-        Cmt2300a() {}
+        Cmt2300a()
+            : lastMillis {0}
+        {}
 
         void setup(uint8_t pinSclk, uint8_t pinSdio, uint8_t pinCsb, uint8_t pinFcsb) {
             mSpi.init(pinSdio, pinSclk, pinCsb, pinFcsb);
@@ -182,6 +187,7 @@ class Cmt2300a {
                 if(CMT2300A_MASK_TX_DONE_FLG == mSpi.readReg(CMT2300A_CUS_INT_CLR1)) {
                     if(cmtSwitchStatus(CMT2300A_GO_STBY, CMT2300A_STA_STBY)) {
                         mTxPending = false;
+                        lastMillis = 0;
                         goRx();
                     }
                 }
@@ -226,9 +232,6 @@ class Cmt2300a {
         }
 
         CmtStatus getRx(uint8_t buf[], uint8_t *rxLen, uint8_t maxlen, int8_t *rssi) {
-            if(mTxPending)
-                return CmtStatus::ERR_TX_PENDING;
-
             if(0x1b != (mSpi.readReg(CMT2300A_CUS_INT_FLAG) & 0x1b))
                 return CmtStatus::FIFO_EMPTY;
 
@@ -252,8 +255,19 @@ class Cmt2300a {
         }
 
         CmtStatus tx(uint8_t buf[], uint8_t len) {
-            if(mTxPending)
-                return CmtStatus::ERR_TX_PENDING;
+            if(mTxPending) {
+                if(CmtTimeoutMs < (millis() - lastMillis)) {
+                    DPRINT(DBG_ERROR, "CMT, last TX timeout: ");
+                    DBGPRINT(String(millis() - lastMillis));
+                    DBGPRINTLN("ms");
+                }
+
+                while(mTxPending && (CmtTimeoutMs > (millis() - lastMillis))) {
+                    vTaskDelay(10);
+                }
+                mTxPending = false;
+                goRx();
+            }
 
             if(mInRxMode) {
                 mInRxMode = false;
@@ -284,6 +298,7 @@ class Cmt2300a {
 
             if(!cmtSwitchStatus(CMT2300A_GO_TX, CMT2300A_STA_TX))
                 return CmtStatus::ERR_SWITCH_STATE;
+            lastMillis = millis();
 
             // wait for tx done
             mTxPending = true;
@@ -560,6 +575,8 @@ class Cmt2300a {
         uint8_t mCusIntFlag = 0;
         uint8_t mRqstCh = 0, mCurCh = 0;
         RegionCfg mRegionCfg = RegionCfg::EUROPE;
+
+        uint32_t lastMillis;
 };
 
 #endif /*__CMT2300A_H__*/
diff --git a/src/web/html/update.html b/src/web/html/update.html
index 4b670d45..410fe452 100644
--- a/src/web/html/update.html
+++ b/src/web/html/update.html
@@ -50,7 +50,9 @@
             }
 
             function hide() {
-                var bin = document.getElementsByName("update")[0].value.slice(-env.length-4, -4)
+                let fw = document.getElementsByName("update")[0].value
+                var bin = fw.slice(-env.length-4, -4)
+                let ver = fw.split("_")[2].split(".")
                 if (bin !== env) {
                     var html = ml("div", {class: "row"}, [
                         ml("div", {class: "row my-3"}, "{#WARN_DIFF_ENV}"),
@@ -60,8 +62,20 @@
                         ])
                     ])
                     modal("{#UPDATE_MODAL}", html)
-                } else
-                    start()
+                } else {
+                    if(ver[1] != "9")
+                        start()
+                    else {
+                        var html = ml("div", {class: "row"}, [
+                            ml("div", {class: "row my-3"}, "{#ERROR_UPGRADE_NOT_POSSIBLE}"),
+                            ml("div", {class: "row"}, [
+                                ml("div", {class: "col-6"}, ml("input", {type: "button", class: "btn", value: "{#CANCEL}", onclick: function() { modalClose(); }}, null))
+                            ])
+                        ])
+                        modal("{#UPDATE_MODAL}", html)
+                    }
+                }
+
             }
 
             function start() {
diff --git a/src/web/lang.json b/src/web/lang.json
index a1f15451..96f60a54 100644
--- a/src/web/lang.json
+++ b/src/web/lang.json
@@ -1333,6 +1333,11 @@
                     "en": "your environment may not match the update file!",
                     "de": "Die ausgew&auml;hlte Firmware passt u.U. nicht zum Chipsatz!"
                 },
+                {
+                    "token": "ERROR_UPGRADE_NOT_POSSIBLE",
+                    "en": "OTA updade to version 0.9.x not possible, partition layout changed",
+                    "de": "Aktualisierung auf Version 0.9.x nicht per Update m&ouml;glich (Partition Layout ge&auml;ndert), bitte per Websinstaller neu installieren"
+                },
                 {
                     "token": "CONTIUE",
                     "en": "continue",