diff --git a/core/recovery.c b/core/recovery.c
index 18a88ba..07f1c99 100644
--- a/core/recovery.c
+++ b/core/recovery.c
@@ -284,7 +284,6 @@ static int recovery_handle_write(eos_slot_t slot, uint32_t offset, uint16_t len)
     /* offset/len come straight from the wire; without this check a
      * recovery client can write past the slot boundary into the other
      * slot, boot-control blocks, or the boot log. */
-    uint32_t slot_size = eos_hal_slot_size(slot);
     if (slot_size == 0 || (uint64_t)offset + len > (uint64_t)slot_size)
         return recovery_send_nack();
 
@@ -514,4 +513,4 @@ int eos_recovery_enter(eos_bootctl_t *bctl)
     }
 
     return EOS_OK;
-}
+}
\ No newline at end of file
diff --git a/include/eos_image.h b/include/eos_image.h
index 049e6c8..a2a9d18 100644
--- a/include/eos_image.h
+++ b/include/eos_image.h
@@ -146,7 +146,7 @@ int eos_crc32_checked(uint32_t addr, size_t len, uint32_t *out_crc);
  * @param len   Length in bytes.
  * @return CRC32 value, or 0 if the region could not be read.
  */
-int eos_crc32(uint32_t addr, size_t len, uint32_t *out);
+uint32_t eos_crc32(uint32_t addr, size_t len);
 
 #ifdef __cplusplus
 }