diff --git a/sd/card.go b/sd/card.go
index d64d281..7a4feb5 100644
--- a/sd/card.go
+++ b/sd/card.go
@@ -95,39 +95,6 @@ func (d *SPICard) CSD() CSD { return d.csd }
 
 func (d *SPICard) yield() { time.Sleep(d.wait) }
 
-func (d *SPICard) waitNotBusy(timeout time.Duration) error {
-	if _, ok := d.waitToken(timeout, 0xff); ok {
-		return nil
-	}
-	return errBusyTimeout
-}
-
-func (d *SPICard) waitStartBlock() error {
-	if _, ok := d.waitToken(d.timeout, tokSTART_BLOCK); ok {
-		return nil
-	}
-	return errWaitStartBlock
-}
-
-// waitToken transmits over SPI waiting to read a given byte token. If argument tok
-// is 0xff then waitToken will wait for a token that does NOT match 0xff.
-func (d *SPICard) waitToken(timeout time.Duration, tok byte) (byte, bool) {
-	tm := d.timers[1].setTimeout(timeout)
-	for {
-		received, err := d.bus.Transfer(0xFF)
-		if err != nil {
-			return received, false
-		}
-		matchTok := received == tok
-		if matchTok || (!matchTok && tok == 0xff) {
-			return received, true
-		} else if tm.expired() {
-			return received, false
-		}
-		d.yield()
-	}
-}
-
 var timeoutTimer [2]timer
 
 type timer struct {
diff --git a/sd/responses.go b/sd/responses.go
index 7c50763..90f74e9 100644
--- a/sd/responses.go
+++ b/sd/responses.go
@@ -84,23 +84,6 @@ func makeResponseError(status response1) error {
 	}
 }
 
-// func (c *SPICard) lastR1() r1 { return c.lastr1 }
-
-// is part of specification but not used in every implementation out there...
-func (d *SPICard) readR1() (resp r1, err error) {
-	first, ok := d.waitToken(d.timeout, 0xff)
-	if !ok {
-		return resp, errBusyTimeout
-	}
-	err = d.bus.Tx(nil, d.buf[1:6])
-	if err != nil {
-		return resp, err
-	}
-	d.buf[0] = first
-	copy(resp.data[:], d.buf[:6])
-	return resp, nil
-}
-
 // Commands used to help generate this file:
 //   - stringer -type=state -trimprefix=state -output=state_string.go
 //   - stringer -type=status -trimprefix=status -output=status_string.go
diff --git a/sd/rustref.go b/sd/rustref.go
index 552c747..76a959d 100644
--- a/sd/rustref.go
+++ b/sd/rustref.go
@@ -200,7 +200,7 @@ func (d *SPICard) WriteBlocks(data []byte, startBlockIdx int64) error {
 	}
 	d.csEnable(true)
 	defer d.csEnable(false)
-
+	writeTimeout := 2 * d.timeout
 	if numblocks == 1 {
 		_, err = d.card_command(cmdWriteBlock, uint32(startBlockIdx))
 		if err != nil {
@@ -210,7 +210,7 @@ func (d *SPICard) WriteBlocks(data []byte, startBlockIdx int64) error {
 		if err != nil {
 			return err
 		}
-		err = d.wait_not_busy()
+		err = d.wait_not_busy(writeTimeout)
 		if err != nil {
 			return err
 		}
@@ -238,7 +238,7 @@ func (d *SPICard) WriteBlocks(data []byte, startBlockIdx int64) error {
 
 		for i := 0; i < numblocks; i++ {
 			offset := i * blocksize
-			err = d.waitNotBusy(d.timeout)
+			err = d.wait_not_busy(writeTimeout)
 			if err != nil {
 				return err
 			}
@@ -248,7 +248,7 @@ func (d *SPICard) WriteBlocks(data []byte, startBlockIdx int64) error {
 			}
 		}
 		// Stop the multi write operation.
-		err = d.waitNotBusy(d.timeout)
+		err = d.wait_not_busy(writeTimeout)
 		if err != nil {
 			return err
 		}
@@ -310,7 +310,7 @@ func (d *SPICard) card_acmd(acmd appcommand, args uint32) (uint8, error) {
 
 func (d *SPICard) card_command(cmd command, args uint32) (uint8, error) {
 	const transmitterBit = 1 << 6
-	err := d.wait_not_busy()
+	err := d.wait_not_busy(d.timeout)
 	if err != nil {
 		return 0, err
 	}
@@ -364,8 +364,8 @@ func (d *SPICard) read_data(data []byte) (err error) {
 	return nil
 }
 
-func (s *SPICard) wait_not_busy() error {
-	tm := s.timers[1].setTimeout(s.timeout)
+func (s *SPICard) wait_not_busy(timeout time.Duration) error {
+	tm := s.timers[1].setTimeout(timeout)
 	for {
 		tok, err := s.receive()
 		if err != nil {