diff --git a/bsp_hosted/OBSWConfig.h.in b/bsp_hosted/OBSWConfig.h.in
index 6e525e5a..41515578 100644
--- a/bsp_hosted/OBSWConfig.h.in
+++ b/bsp_hosted/OBSWConfig.h.in
@@ -48,6 +48,7 @@
 #define OBSW_SWITCH_TO_NORMAL_MODE_AFTER_STARTUP    1
 #define OBSW_PRINT_MISSED_DEADLINES                 1
 
+#define OBSW_MPSOC_JTAG_BOOT                        0
 #define OBSW_SYRLINKS_SIMULATED                     1
 #define OBSW_ADD_TEST_CODE                          0
 #define OBSW_ADD_TEST_TASK                          0
diff --git a/linux/payload/plocMpsocHelpers.h b/linux/payload/plocMpsocHelpers.h
index ef03359d..2c9645d8 100644
--- a/linux/payload/plocMpsocHelpers.h
+++ b/linux/payload/plocMpsocHelpers.h
@@ -850,7 +850,9 @@ class TcSimplexSendFile : public TcBase {
     if (result != returnvalue::OK) {
       return result;
     }
-    if (chunkParameter == 0) {
+    /// No chunks makes no sense, and DIV str can not be longer than whats representable with 3
+    /// decimal digits.
+    if (chunkParameter == 0 or chunkParameter > 999) {
       return INVALID_PARAMETER;
     }
     std::string fileName(reinterpret_cast<const char*>(*dataPtr));
@@ -860,8 +862,8 @@ class TcSimplexSendFile : public TcBase {
     size_t currentCopyIdx = 0;
     size_t payloadLen = fileName.length() + sizeof(NULL_TERMINATOR) + CRC_SIZE;
     if (chunkParameter > 1) {
-      char divStr[12]{};
-      sprintf(divStr, "DIV%03d", chunkParameter);
+      char divStr[16]{};
+      sprintf(divStr, "DIV%03u", chunkParameter);
       std::memcpy(payloadStart, divStr, DIV_STR_LEN);
       payloadLen += DIV_STR_LEN;
       currentCopyIdx += DIV_STR_LEN;
diff --git a/unittest/CMakeLists.txt b/unittest/CMakeLists.txt
index e9a01891..808a68ef 100644
--- a/unittest/CMakeLists.txt
+++ b/unittest/CMakeLists.txt
@@ -6,5 +6,6 @@ target_sources(${UNITTEST_NAME} PRIVATE
     testEnvironment.cpp
     testGenericFilesystem.cpp
     hdlcEncodingRw.cpp
+    mpsocTests.cpp
     printChar.cpp
-)
\ No newline at end of file
+)
diff --git a/unittest/mpsocTests.cpp b/unittest/mpsocTests.cpp
new file mode 100644
index 00000000..2ab11b21
--- /dev/null
+++ b/unittest/mpsocTests.cpp
@@ -0,0 +1,14 @@
+
+#include <catch2/catch_test_macros.hpp>
+
+TEST_CASE("MPSoC helper tests", "[payload]") {
+  char divStr[16]{};
+  uint32_t divParam = 0;
+
+  SECTION("Simple Test") {
+    divParam = 3;
+    CHECK(divParam < 999);
+    sprintf(divStr, "DIV%03u", divParam);
+    REQUIRE(strcmp(divStr, "DIV003") == 0);
+  }
+}