diff --git a/demos/Win32-MinGW/main.c b/demos/Win32-MinGW/main.c
index 1d80b9d76..c2ac24868 100644
--- a/demos/Win32-MinGW/main.c
+++ b/demos/Win32-MinGW/main.c
@@ -194,7 +194,7 @@ static msg_t ShellThread(void *arg) {
       else if (stricmp(lp, "time") == 0) {
         if (checkend(sd))
           continue;
-        sprintf(line, "Time: %d\r\n", chSysGetTime());
+        sprintf(line, "Time: %d\r\n", chTimeNow());
         PrintLineFDD(sd, line);
       }
       else if (stricmp(lp, "hello") == 0) {
diff --git a/docs/src/concepts.dox b/docs/src/concepts.dox
index d8d874bac..8ef626c01 100644
--- a/docs/src/concepts.dox
+++ b/docs/src/concepts.dox
@@ -34,9 +34,9 @@
  * @section naming Naming Conventions
  * ChibiOS/RT APIs are all named following this convention:
  * @a ch\<group\>\<action\>\<suffix\>().
- * The possible groups are: @a Sys, @a Sch, @a VT, @a Thd, @a Sem, @a Mtx,
- * @a Cond, @a Evt, @a Msg, @a IQ, @a OQ, @a HQ, @a FDD, @a HDD, @a Dbg,
- * @a Heap, @a Pool.
+ * The possible groups are: @a Sys, @a Sch, @a Time @a VT, @a Thd, @a Sem,
+ * @a Mtx, @a Cond, @a Evt, @a Msg, @a IQ, @a OQ, @a HQ, @a FDD, @a HDD,
+ * @a Dbg, @a Heap, @a Pool.
  *
  * @section api_suffixes API Names Suffixes
  * The suffix can be one of the following:
diff --git a/docs/src/timing.dox b/docs/src/timing.dox
index 9fd19545d..7732bef0b 100644
--- a/docs/src/timing.dox
+++ b/docs/src/timing.dox
@@ -46,7 +46,7 @@ msg_t my_thread(void *param) {
  * @code
 msg_t my_thread(void *param) {
 
-  systick_t time = chSysGetTime();  /* T0 */
+  systick_t time = chTimeNow();     /* T0 */
   while (TRUE) {
     time += MS2ST(1000);            /* Next deadline */
     do_something();
diff --git a/readme.txt b/readme.txt
index ef9fcf4e0..5c3163a41 100644
--- a/readme.txt
+++ b/readme.txt
@@ -75,7 +75,13 @@ Win32-MinGW            - ChibiOS/RT simulator and demo into a WIN32 process,
 *** 1.1.2unstable ***
 - FIX: Fixed priority inheritance problem with condvars (bug 2674756) and
   added a specific test case to the test suite (backported in stable branch).
+- FIX: Fixed a wrong parameter check in chVTSetI() (bug 2679155).
+- FIX: Build error with options CH_USE_NESTED_LOCKS && !CH_OPTIMIZE_SPEED
+  (bug 2678928).
 - FIX: Removed unused chSysPuts() macro (bug 2672678).
+- FIX: Renamed function chSysInTimeWindow() as chTimeIsWithin() and renamed
+  the macro chSysGetTime() in chTimeNow(), the old names are still recognized
+  but marked as deprecated (fixes the bug 2678953 but goes a bit further).
 - Removed testcond.c|h and moved the test cases into testmtx.c. Mutexes and
   condvars have to be tested together.
 - Added architecture diagram to the documentation.
diff --git a/src/chsys.c b/src/chsys.c
index 20c1e17fb..666d0cfef 100644
--- a/src/chsys.c
+++ b/src/chsys.c
@@ -110,14 +110,18 @@ void chSysTimerHandlerI(void) {
 #if CH_USE_NESTED_LOCKS && !CH_OPTIMIZE_SPEED
 void chSysLock(void) {
 
-  chDbgAssert(currp->p_locks >= 0, "chinit.c, chSysLock()");
+  chDbgAssert(currp->p_locks >= 0,
+              "chSysLock(), #1",
+              "negative nesting counter");
   if (currp->p_locks++ == 0)
     port_lock();
 }
 
 void chSysUnlock(void) {
 
-  chDbgAssert(currp->p_locks > 0, "chinit.c, chSysUnlock()");
+  chDbgAssert(currp->p_locks > 0,
+              "chSysUnlock(), #1",
+              "non-positive nesting counter");
   if (--currp->p_locks == 0)
     port_unlock();
 }
diff --git a/src/chthreads.c b/src/chthreads.c
index a22514f09..70db14130 100644
--- a/src/chthreads.c
+++ b/src/chthreads.c
@@ -290,7 +290,7 @@ void chThdSleep(systime_t time) {
 void chThdSleepUntil(systime_t time) {
 
   chSysLock();
-  if ((time -= chSysGetTime()) > 0)
+  if ((time -= chTimeNow()) > 0)
     chThdSleepS(time);
   chSysUnlock();
 }
diff --git a/src/chvt.c b/src/chvt.c
index 76ab6a7f3..9d4fec138 100644
--- a/src/chvt.c
+++ b/src/chvt.c
@@ -19,7 +19,7 @@
 
 /**
  * @file chvt.c
- * @brief Time related code.
+ * @brief Time and Virtual Timers related code.
  * @addtogroup Time
  * @{
  */
@@ -58,8 +58,8 @@ void vt_init(void) {
 void chVTSetI(VirtualTimer *vtp, systime_t time, vtfunc_t vtfunc, void *par) {
   VirtualTimer *p;
 
-  chDbgCheck((vtp != NULL) && (vtfunc != NULL) &&
-             (time != TIME_IMMEDIATE) && (time != TIME_INFINITE), "chVTSetI");
+  chDbgCheck((vtp != NULL) && (vtfunc != NULL) && (time != TIME_INFINITE),
+             "chVTSetI");
 
   vtp->vt_par = par;
   vtp->vt_func = vtfunc;
@@ -103,9 +103,9 @@ void chVTResetI(VirtualTimer *vtp) {
  * @retval TRUE current time within the specified time window.
  * @retval FALSE current time not within the specified time window.
  */
-bool_t chSysInTimeWindow(systime_t start, systime_t end) {
+bool_t chTimeIsWithin(systime_t start, systime_t end) {
 
-  systime_t time = chSysGetTime();
+  systime_t time = chTimeNow();
   return end >= start ? (time >= start) && (time < end) :
                         (time >= start) || (time < end);
 }
diff --git a/src/include/sys.h b/src/include/sys.h
index 90fbfd1a1..a84d33da8 100644
--- a/src/include/sys.h
+++ b/src/include/sys.h
@@ -171,6 +171,10 @@ extern "C" {
 #endif
   void chSysInit(void);
   void chSysTimerHandlerI(void);
+#if CH_USE_NESTED_LOCKS && !CH_OPTIMIZE_SPEED
+  void chSysLock(void);
+  void chSysUnlock(void);
+#endif /* CH_USE_NESTED_LOCKS && !CH_OPTIMIZE_SPEED */
 #ifdef __cplusplus
 }
 #endif
diff --git a/src/include/vt.h b/src/include/vt.h
index e104bb101..e736e1af0 100644
--- a/src/include/vt.h
+++ b/src/include/vt.h
@@ -104,7 +104,7 @@ extern "C" {
   void vt_init(void);
   void chVTSetI(VirtualTimer *vtp, systime_t time, vtfunc_t vtfunc, void *par);
   void chVTResetI(VirtualTimer *vtp);
-  bool_t chSysInTimeWindow(systime_t start, systime_t end);
+  bool_t chTimeIsWithin(systime_t start, systime_t end);
 #ifdef __cplusplus
 }
 #endif
@@ -118,8 +118,20 @@ extern "C" {
  * @note The counter can reach its maximum and then returns to zero.
  * @note This function is designed to work with the @p chThdSleepUntil().
  */
-#define chSysGetTime() (vtlist.vt_systime)
+#define chTimeNow() (vtlist.vt_systime)
 
+/**
+ * Provided for backward compatibility.
+ * @deprecated Will be removed in 1.2.0.
+ */
+#define chSysGetTime() chTimeNow()
+
+/**
+ * Provided for backward compatibility.
+ * @deprecated Will be removed in 1.2.0.
+ */
+#define chSysInTimeWindow(start, end) chTimeIsWithin(start, end)
+ 
 #endif /* _VT_H_ */
 
 /** @} */
diff --git a/test/test.c b/test/test.c
index be3c8d9c5..3be813bb2 100644
--- a/test/test.c
+++ b/test/test.c
@@ -146,7 +146,7 @@ bool_t _test_assert_sequence(char *expected) {
 
 bool_t _test_assert_time_window(systime_t start, systime_t end) {
 
-  return _test_assert(chSysInTimeWindow(start, end), "time window error");
+  return _test_assert(chTimeIsWithin(start, end), "time window error");
 }
 
 /*
@@ -171,8 +171,8 @@ void test_wait_threads(void) {
 void test_cpu_pulse(unsigned ms) {
 
   systime_t duration = MS2ST(ms);
-  systime_t start = chSysGetTime();
-  while (chSysInTimeWindow(start, start + duration)) {
+  systime_t start = chTimeNow();
+  while (chTimeIsWithin(start, start + duration)) {
 #if defined(WIN32)
     ChkIntSources();
 #endif
@@ -182,7 +182,7 @@ void test_cpu_pulse(unsigned ms) {
 systime_t test_wait_tick(void) {
 
   chThdSleep(1);
-  return chSysGetTime();
+  return chTimeNow();
 }
 
 /*
diff --git a/test/testevt.c b/test/testevt.c
index 192c6e6be..9c6f7bf6e 100644
--- a/test/testevt.c
+++ b/test/testevt.c
@@ -77,7 +77,7 @@ static void evt1_execute(void) {
   chEvtInit(&es2);
   chEvtRegisterMask(&es1, &el1, 1);
   chEvtRegisterMask(&es2, &el2, 4);
-  target_time = chSysGetTime() + MS2ST(50);
+  target_time = chTimeNow() + MS2ST(50);
   threads[0] = chThdCreateStatic(wa[0], WA_SIZE, chThdGetPriority()-1, thread, "A");
   m = chEvtWaitAll(5);
   test_assert_time_window(target_time, target_time + ALLOWED_DELAY);
diff --git a/test/testsem.c b/test/testsem.c
index 2482f1295..e954871d5 100644
--- a/test/testsem.c
+++ b/test/testsem.c
@@ -86,7 +86,7 @@ static void sem2_execute(void) {
   msg= chSemWaitTimeout(&sem1, TIME_IMMEDIATE);
   test_assert(msg == RDY_TIMEOUT, "#1");
 
-  target_time = chSysGetTime() + MS2ST(5 * 500);
+  target_time = chTimeNow() + MS2ST(5 * 500);
   for (i = 0; i < 5; i++) {
     test_emit_token('A' + i);
     msg = chSemWaitTimeout(&sem1, MS2ST(500));