diff --git a/libraries/AP_HAL/utility/sparse-endian.h b/libraries/AP_HAL/utility/sparse-endian.h
index 37248c728a..dc826623cc 100644
--- a/libraries/AP_HAL/utility/sparse-endian.h
+++ b/libraries/AP_HAL/utility/sparse-endian.h
@@ -86,13 +86,17 @@ static inline uint64_t be64toh(be64_t value) { return bswap_64_on_le((uint64_t _
 
 // methods for misaligned buffers
 static inline uint16_t le16toh_ptr(const uint8_t *p) { return p[0] | (p[1]<<8U); }
+static inline uint32_t le24toh_ptr(const uint8_t *p) { return p[0] | (p[1]<<8U) | (p[2]<<16U); }
 static inline uint32_t le32toh_ptr(const uint8_t *p) { return p[0] | (p[1]<<8U) | (p[2]<<16U) | (p[3]<<24U); }
 static inline uint16_t be16toh_ptr(const uint8_t *p) { return p[1] | (p[0]<<8U); }
+static inline uint32_t be24toh_ptr(const uint8_t *p) { return p[2] | (p[1]<<8U) | (p[0]<<16U); }
 static inline uint32_t be32toh_ptr(const uint8_t *p) { return p[3] | (p[2]<<8U) | (p[1]<<16U) | (p[0]<<24U); }
 
 static inline void put_le16_ptr(uint8_t *p, uint16_t v) { p[0] = (v&0xFF); p[1] = (v>>8); }
+static inline void put_le24_ptr(uint8_t *p, uint32_t v) { p[0] = (v&0xFF); p[1] = (v>>8)&0xFF; p[2] = (v>>16)&0xFF; }
 static inline void put_le32_ptr(uint8_t *p, uint32_t v) { p[0] = (v&0xFF); p[1] = (v>>8)&0xFF; p[2] = (v>>16)&0xFF; p[3] = (v>>24)&0xFF; }
 static inline void put_be16_ptr(uint8_t *p, uint16_t v) { p[1] = (v&0xFF); p[0] = (v>>8); }
+static inline void put_be24_ptr(uint8_t *p, uint32_t v) { p[2] = (v&0xFF); p[1] = (v>>8)&0xFF; p[0] = (v>>16)&0xFF; }
 static inline void put_be32_ptr(uint8_t *p, uint32_t v) { p[3] = (v&0xFF); p[2] = (v>>8)&0xFF; p[1] = (v>>16)&0xFF; p[0] = (v>>24)&0xFF; }
 
 #undef __ap_bitwise