Successfully blackbox logged 46kB of flawless log data on the bench

Data read back using MSP

src/main/io/flashfs.c

@@ -401,9 +401,17 @@ void flashfsWrite(const uint8_t *data, unsigned int len)
  */
 int flashfsRead(uint8_t *data, unsigned int len)
 {
-    int result = m25p16_readBytes(tailAddress, data, len);
+    int bytesRead;
 
-    flashfsSetTailAddress(tailAddress + result);
+    // Did caller try to read past the end of the volume?
-
+    if (tailAddress + len > flashfsGetSize()) {
-    return result;
+        // Truncate their request
+        len = flashfsGetSize() - tailAddress;
+    }
+
+    bytesRead = m25p16_readBytes(tailAddress, data, len);
+
+    flashfsSetTailAddress(tailAddress + bytesRead);
+
+    return bytesRead;
 }

src/main/io/serial_msp.c

@@ -551,6 +551,7 @@ static void serializeDataflashReadReply(uint32_t address, uint8_t size)
     enum { DATAFLASH_READ_REPLY_CHUNK_SIZE = 128 };
 
     uint8_t buffer[DATAFLASH_READ_REPLY_CHUNK_SIZE];
+    int bytesRead;
 
     if (size > DATAFLASH_READ_REPLY_CHUNK_SIZE) {
         size = DATAFLASH_READ_REPLY_CHUNK_SIZE;
@@ -561,9 +562,10 @@ static void serializeDataflashReadReply(uint32_t address, uint8_t size)
     serialize32(address);
 
     flashfsSeekAbs(address);
-    flashfsRead(buffer, size);
+    // bytesRead will be lower than that requested if we reach end of volume
+    bytesRead = flashfsRead(buffer, size);
 
-    for (int i = 0; i < size; i++) {
+    for (int i = 0; i < bytesRead; i++) {
         serialize8(buffer[i]);
     }
 }
@@ -1203,9 +1205,8 @@ static bool processOutCommand(uint8_t cmdMSP)
     case MSP_DATAFLASH_READ:
         {
             uint32_t readAddress = read32();
-            uint8_t readSize = read8();
 
-            serializeDataflashReadReply(readAddress, readSize);
+            serializeDataflashReadReply(readAddress, 128);
         }
         break;
 #endif