diff --git a/firmware/controllers/error_handling.cpp b/firmware/controllers/error_handling.cpp
index 0dbbc03cd5..cd4f311720 100644
--- a/firmware/controllers/error_handling.cpp
+++ b/firmware/controllers/error_handling.cpp
@@ -170,6 +170,15 @@ uint32_t lastLockTime;
  */
 uint32_t maxLockedDuration = 0;
 
+/**
+ * this depends on chdebug.h patch
+ #if CH_DBG_SYSTEM_STATE_CHECK == TRUE
+-#define _dbg_enter_lock() (ch.dbg.lock_cnt = (cnt_t)1)
+-#define _dbg_leave_lock() (ch.dbg.lock_cnt = (cnt_t)0)
++#define _dbg_enter_lock() {(ch.dbg.lock_cnt = (cnt_t)1);  ON_LOCK_HOOK;}
++#define _dbg_leave_lock() {ON_UNLOCK_HOOK;(ch.dbg.lock_cnt = (cnt_t)0);}
+ #endif
+ */
 void onLockHook(void) {
 	lastLockTime = GET_TIMESTAMP();
 }
diff --git a/firmware/docs/rusefi_custom_chibios.txt b/firmware/docs/rusefi_custom_chibios.txt
index bf8d5fd5fd..151cc9b8ca 100644
--- a/firmware/docs/rusefi_custom_chibios.txt
+++ b/firmware/docs/rusefi_custom_chibios.txt
@@ -2,28 +2,25 @@ rusEfi is trying to use latest stable ChibiOS with minimal changes
 
 At the moment rusEfi custom version of ChibiOS has the following changes:
 
-1) LSE auto-detection, see rusefi_lse_fix.h see LSE_TIMEOUT
+*) minor OS monitoring and maintainability fixes:
+   chDbgStackOverflowPanic allows to know which thread has stack overflow
+   maxNesting good to know maximum ISR depth
+   ON_LOCK_HOOK is used to measure durations of critical sections
 
-2) Changed "STM32_ADC_ADC2_DMA_STREAM" in demos/STM32/RT-STM32F334R8-NUCLEO/mcuconf.h
+*) LSE auto-detection, see rusefi_lse_fix.h see LSE_TIMEOUT
+
+*) Support for half/timeout-ISR for UART-DMA in /os/hal/include/uart.h and os/hal/ports/STM32/LLD/USARTv1/uart_lld.* by andreika
+
+Weird changes without an explanation:
 
 3) Uncommented "ASMXOBJS" support in os/common/ports/ARMCMx/compilers/GCC/rules.mk
 
-5) Support for half/timeout-ISR for UART-DMA in /os/hal/include/uart.h and os/hal/ports/STM32/LLD/USARTv1/uart_lld.*
-
-6) Changes around "FLOAT_PRECISION" and ftoa() in os/hal/lib/streams/chprintf.c
-
 8) Use local "struct tm *t" in os/hal/ports/STM32/LLD/RTCv1/rtc_lld.c
 
 11) Fixes for UART4-UART8, USART_ISR_* flags USART_CR1_M in os/hal/ports/STM32/LLD/USARTv2/serial_lld.c and os/hal/ports/STM32/LLD/USARTv2/uart_lld.c
 
-13) ON_LOCK_HOOK fix in os/rt/include/chdebug.h
-
-14) Use chSysHalt() instead of chDbgStackOverflowPanic() in os/rt/ports/ARM/chcore.h
-
 15) Use QueryPerformanceCounter() instead of POSIX gettimeofday() in os/rt/ports/SIMIA32/chcore.c
 
-16) Change chSysHalt() and remove maxNesting in os/rt/src/chdebug.c
-
 New files: 
 	os/common/startup/SIMIA32/compilers/GCC/rules.mk
 	os/hal/ports/STM32/LLD/RTCv2/rusefi_lse_fix.h
diff --git a/firmware/rusefi.cpp b/firmware/rusefi.cpp
index ddd4602519..7bc2469db6 100644
--- a/firmware/rusefi.cpp
+++ b/firmware/rusefi.cpp
@@ -235,6 +235,15 @@ void runRusEfi(void) {
 	}
 }
 
+/**
+ * this depends on chcore.h patch
++void chDbgStackOverflowPanic(thread_t *otp);
++
+-    chSysHalt("stack overflow");                                            \
++    chDbgStackOverflowPanic(otp);                                           \
+
+ *
+ */
 void chDbgStackOverflowPanic(thread_t *otp) {
 	(void)otp;
 	strcpy(panicMessage, "stack overflow: ");