diff --git a/include/Modbus/BusList.h b/include/Modbus/BusList.h
index 362bd03f..17f94a03 100644
--- a/include/Modbus/BusList.h
+++ b/include/Modbus/BusList.h
@@ -40,7 +40,7 @@ namespace Modbus {
  * Error thrown when a response is missing. This is mostly caused by an @glos{ILC} on
  * the bus being dead/not reacting to the command send.
  */
-class MissingResponse : std::runtime_error {
+class MissingResponse : public std::runtime_error {
 public:
     /**
      * Construct missing response exception.
@@ -49,7 +49,7 @@ class MissingResponse : std::runtime_error {
      * @param func Expected function which wasn't responded by the @glos{ILC}
      */
     MissingResponse(uint8_t address, uint8_t func)
-            : std::runtime_error(fmt::format("Missing response for function {} from ILC with address {}",
+            : std::runtime_error(fmt::format("Missing response for function {0} (0x{0:02x}) from ILC with address {1}",
                                              func, address)) {}
 };
 
@@ -59,7 +59,7 @@ class MissingResponse : std::runtime_error {
  *
  * @see BusList::addResponse
  */
-class UnexpectedResponse : std::runtime_error {
+class UnexpectedResponse : public std::runtime_error {
 public:
     /**
      * Construct unexpected response.
diff --git a/include/Modbus/Parser.h b/include/Modbus/Parser.h
index 13300f92..c21ff963 100644
--- a/include/Modbus/Parser.h
+++ b/include/Modbus/Parser.h
@@ -31,6 +31,8 @@
 #include <string>
 #include <vector>
 
+#include <spdlog/fmt/fmt.h>
+
 #include <Modbus/Buffer.h>
 
 namespace Modbus {
@@ -78,7 +80,7 @@ class CRCError : public std::runtime_error {
 /**
  * Thrown when response continue after CRC.
  */
-class LongResponse : std::runtime_error {
+class LongResponse : public std::runtime_error {
 public:
     /**
      * Construct LongResponse from the given buffer.
@@ -124,7 +126,7 @@ class Parser : public std::vector<uint8_t> {
      */
     void readBuffer(void *buf, size_t len) {
         if (_data + len > size()) {
-            throw std::out_of_range("Trying to access data beyond buffer are.");
+            throw std::out_of_range(fmt::format("Attempt to access data beyond buffer end (buffer index {}, but buffer length is {}).", _data + len, size()));
         }
         memcpy(buf, data() + _data, len);
         _data += len;
diff --git a/src/ILC/ILCBusList.cpp b/src/ILC/ILCBusList.cpp
index b9984af7..822c7cbe 100644
--- a/src/ILC/ILCBusList.cpp
+++ b/src/ILC/ILCBusList.cpp
@@ -189,7 +189,7 @@ std::vector<const char *> ILCBusList::getFaultString(uint16_t fault) {
 void ILCBusList::changeILCMode(uint8_t address, uint16_t mode) {
     uint32_t timeout = 335;
     try {
-        if ((getLastMode(address) == Mode::Standby && mode == Mode::Bootloader) ||
+        if ((mode == Mode::Bootloader) ||
             (getLastMode(address) == Mode::Bootloader && mode == Mode::Standby)) {
             timeout = 100000;
         }
diff --git a/src/LSST/cRIO/FPGA.cpp b/src/LSST/cRIO/FPGA.cpp
index 63f993b1..31417710 100644
--- a/src/LSST/cRIO/FPGA.cpp
+++ b/src/LSST/cRIO/FPGA.cpp
@@ -91,12 +91,13 @@ void FPGA::ilcCommands(ILC::ILCBusList &ilc, int32_t timeout) {
     uint16_t responseLen;
 
     readU16ResponseFIFO(&responseLen, 1, 20);
-    if (responseLen < 4) {
+    // minimal response is timestamp + 4 ILC bytes
+    if (responseLen < 8) {
         if (responseLen > 0) {
             uint16_t buffer[responseLen];
             readU16ResponseFIFO(buffer, responseLen, 10);
         }
-        throw std::runtime_error("FPGA::ilcCommands timeout on response: " + std::to_string(responseLen));
+        throw Modbus::MissingResponse(ilc[0].buffer.address(), ilc[0].buffer.func());
     }
 
     uint16_t buffer[responseLen];