little fixes to make everything actually work
diff --git a/bbb_cape/src/bbb/crc.h b/bbb_cape/src/bbb/crc.h
index 4d1dea7..c26f5db 100644
--- a/bbb_cape/src/bbb/crc.h
+++ b/bbb_cape/src/bbb/crc.h
@@ -16,7 +16,7 @@
// length is the number of bytes of data to read. It must be a multiple of 4.
// initial can be a previous return value to continue the same checksum over
// more data.
-uint32_t CalculateChecksum(uint8_t *data, size_t length,
+uint32_t CalculateChecksum(const uint8_t *data, size_t length,
uint32_t initial = 0xFFFFFFFF);
// Reads all data out of reader and does a checksum over all of it in reasonably
// sized pieces. Does all of the reads with a timeout of 0. Stops on the first