diff --git a/sd/blockdevice.go b/sd/blockdevice.go
index 2891be5..2ee72b5 100644
--- a/sd/blockdevice.go
+++ b/sd/blockdevice.go
@@ -22,8 +22,8 @@ type Card interface {
 	// ReadBlocks reads the given number of blocks from the card, starting at the given block index.
 	// The dst buffer must be a multiple of the block size.
 	ReadBlocks(dst []byte, startBlockIdx int64) (int, error)
-	// EraseSectors erases sectors starting at startSectorIdx to startSectorIdx+numSectors.
-	EraseSectors(startSectorIdx, numSectors int64) error
+	// EraseBlocks erases blocks starting at startBlockIdx to startBlockIdx+numBlocks.
+	EraseBlocks(startBlock, numBlocks int64) error
 }
 
 // NewBlockDevice creates a new BlockDevice from a Card.
@@ -167,7 +167,7 @@ func (bd *BlockDevice) BlockSize() int64 {
 // supports this. The start and len parameters are in block numbers, use
 // EraseBlockSize to map addresses to blocks.
 func (bd *BlockDevice) EraseBlocks(startEraseBlockIdx, len int64) error {
-	return bd.card.EraseSectors(startEraseBlockIdx, len)
+	return bd.card.EraseBlocks(startEraseBlockIdx, len)
 }
 
 // EraseBlockSize returns the smallest erasable area on this particular chip
diff --git a/sd/spicard.go b/sd/spicard.go
index 8d82cfe..8981357 100644
--- a/sd/spicard.go
+++ b/sd/spicard.go
@@ -267,7 +267,7 @@ func (d *SPICard) ReadBlocks(dst []byte, startBlockIdx int64) (int, error) {
 	panic("unreachable numblocks<=0")
 }
 
-func (d *SPICard) EraseSectors(startSector, numberSectors int64) error {
+func (d *SPICard) EraseBlocks(startBlock, numberOfBlocks int64) error {
 	return errors.New("sd:erase not implemented")
 }