diff --git a/sourcepawn/jit/engine2.cpp b/sourcepawn/jit/engine2.cpp
index 09023cbd..62a5294b 100644
--- a/sourcepawn/jit/engine2.cpp
+++ b/sourcepawn/jit/engine2.cpp
@@ -1,5 +1,6 @@
 // vim: set ts=4 sw=4 tw=99 noet:
 #include <stdio.h>
+#include <stdarg.h>
 #include <stdlib.h>
 #include <string.h>
 #include "engine2.h"
@@ -220,3 +221,15 @@ bool SourcePawnEngine2::InstallWatchdogTimer(size_t timeout_ms)
 	return g_WatchdogTimer.Initialize(timeout_ms);
 }
 
+void LogFatalPCodeError(const char *fmt, ...)
+{
+	FILE *fp = fopen("spjit-fatal-log.txt", "at");
+	if (!fp)
+		return;
+	va_list ap;
+	va_start(ap, fmt);
+	vfprintf(fp, fmt, ap);
+	fprintf(fp, "\n");
+	va_end(ap);
+	fclose(fp);
+}
diff --git a/sourcepawn/jit/engine2.h b/sourcepawn/jit/engine2.h
index e9cb980e..be0bdfe7 100644
--- a/sourcepawn/jit/engine2.h
+++ b/sourcepawn/jit/engine2.h
@@ -45,6 +45,8 @@ namespace SourcePawn
 	};
 }
 
+extern void LogFatalPCodeError(const char *fmt, ...);
+
 extern SourcePawn::SourcePawnEngine2 g_engine2;
 
 #endif //_INCLUDE_SOURCEPAWN_ENGINE_2_H_
diff --git a/sourcepawn/jit/interpreter.cpp b/sourcepawn/jit/interpreter.cpp
index 257e9414..89fca60a 100644
--- a/sourcepawn/jit/interpreter.cpp
+++ b/sourcepawn/jit/interpreter.cpp
@@ -19,6 +19,7 @@
 #include "interpreter.h"
 #include "opcodes.h"
 #include "watchdog_timer.h"
+#include "engine2.h"
 
 #define STACK_MARGIN 64
 
@@ -46,6 +47,10 @@ static inline cell_t *
 Jump(const sp_plugin_t *plugin, sp_context_t *ctx, cell_t target)
 {
   if (!IsValidOffset(target) || uint32_t(target) >= plugin->pcode_size) {
+    LogFatalPCodeError("[i] invalid jump (name=%s) (target=%d)",
+      plugin->name,
+      target
+    );
     ctx->err = SP_ERROR_INVALID_INSTRUCTION;
     return NULL;
   }
@@ -61,6 +66,11 @@ JumpTarget(const sp_plugin_t *plugin, sp_context_t *ctx, cell_t *cip, bool cond)
 
   cell_t target = *cip;
   if (!IsValidOffset(target) || uint32_t(target) >= plugin->pcode_size) {
+    LogFatalPCodeError("[i] invalid jump (name=%s) (cip=%d) (target=%d)",
+      plugin->name,
+      cell_t((uint8_t *)cip - plugin->pcode),
+      target
+    );
     ctx->err = SP_ERROR_INVALID_INSTRUCTION;
     return NULL;
   }
@@ -231,8 +241,14 @@ Interpret(BaseRuntime *rt, uint32_t aCodeStart, cell_t *rval)
   cell_t *code = reinterpret_cast<cell_t *>(plugin->pcode);
   cell_t *codeend = reinterpret_cast<cell_t *>(plugin->pcode + plugin->pcode_size);
 
-  if (!IsValidOffset(aCodeStart) || aCodeStart > plugin->pcode_size)
+  if (!IsValidOffset(aCodeStart) || aCodeStart > plugin->pcode_size) {
+    LogFatalPCodeError("[i] invalid cs (name=%s) (cs=%d) (size=%d)",
+      rt->plugin()->name,
+      aCodeStart,
+      plugin->pcode_size
+    );
     return SP_ERROR_INVALID_INSTRUCTION;
+  }
 
   sp_context_t *ctx = rt->GetBaseContext()->GetCtx();
   ctx->err = SP_ERROR_NONE;
@@ -248,6 +264,11 @@ Interpret(BaseRuntime *rt, uint32_t aCodeStart, cell_t *rval)
 
   for (;;) {
     if (cip >= codeend) {
+      LogFatalPCodeError("[i] cip overrun (name=%s) (cs=%d) (cip=%d)",
+        rt->plugin()->name,
+        aCodeStart,
+        cell_t(cip - code)
+      );
       ctx->err = SP_ERROR_INVALID_INSTRUCTION;
       goto error;
     }
@@ -764,6 +785,11 @@ Interpret(BaseRuntime *rt, uint32_t aCodeStart, cell_t *rval)
       {
         cell_t amount = *cip++;
         if (!IsValidOffset(amount)) {
+          LogFatalPCodeError("[i] invalid stack offset (name=%s) (cs=%d) (cip=%d)",
+            rt->plugin()->name,
+            aCodeStart,
+            cell_t(cip - code)
+          );
           ctx->err = SP_ERROR_INVALID_INSTRUCTION;
           goto error;
         }
@@ -970,6 +996,11 @@ Interpret(BaseRuntime *rt, uint32_t aCodeStart, cell_t *rval)
 
       default:
       {
+        LogFatalPCodeError("[i] unknown instruction (name=%s) (cs=%d) (cip=%d)",
+          rt->plugin()->name,
+          aCodeStart,
+          cell_t(cip - code)
+        );
         ctx->err = SP_ERROR_INVALID_INSTRUCTION;
         goto error;
       }
diff --git a/sourcepawn/jit/x86/jit_x86.cpp b/sourcepawn/jit/x86/jit_x86.cpp
index df68bd57..2f218930 100644
--- a/sourcepawn/jit/x86/jit_x86.cpp
+++ b/sourcepawn/jit/x86/jit_x86.cpp
@@ -323,6 +323,12 @@ JitFunction *
 Compiler::emit(int *errp)
 {
   if (cip_ >= code_end_ || *cip_ != OP_PROC) {
+    LogFatalPCodeError("[j] emit() overran cip (name=%s) (cs=%d) (ce=%d) (cip=%d)",
+      plugin_->name,
+      pcode_start_,
+      cell_t((uint8_t *)cip_ - plugin_->pcode),
+      cell_t((uint8_t *)code_end_ - plugin_->pcode)
+    );
     *errp = SP_ERROR_INVALID_INSTRUCTION;
     return NULL;
   }
@@ -1345,6 +1351,13 @@ Compiler::emitOp(OPCODE op)
       break;
 
     default:
+      LogFatalPCodeError("[j] unknown opcode (name=%s) (cs=%d) (ce=%d) (cip=%d) (op=%d)",
+        plugin_->name,
+        pcode_start_,
+        cell_t((uint8_t *)cip_ - plugin_->pcode),
+        cell_t((uint8_t *)code_end_ - plugin_->pcode),
+        op
+      );
       error_ = SP_ERROR_INVALID_INSTRUCTION;
       return false;
   }
@@ -1544,6 +1557,12 @@ cell_t
 Compiler::readCell()
 {
   if (cip_ >= code_end_) {
+    LogFatalPCodeError("[j] readCell() overran (name=%s) (cs=%d) (ce=%d) (cip=%d)",
+      plugin_->name,
+      pcode_start_,
+      cell_t((uint8_t *)cip_ - plugin_->pcode),
+      cell_t((uint8_t *)code_end_ - plugin_->pcode)
+    );
     error_= SP_ERROR_INVALID_INSTRUCTION;
     return 0;
   }