diff --git a/blk/424 b/blk/424
index 4537302..e6d55fb 100644
--- a/blk/424
+++ b/blk/424
@@ -5,11 +5,6 @@
 ( spix 0xff until the response is something else than 0xff
   for a maximum of 20 times. Returns 0xff if no response. )
 : _wait
-    0  ( cnt )
-    BEGIN
-        _idle
-        DUP 0xff = IF DROP ELSE NIP EXIT THEN
-        1+
-    DUP 20 = UNTIL
-    DROP 0xff
-;
+    0 ( dummy ) 20 0 DO
+        DROP _idle DUP 0xff = NOT IF LEAVE THEN
+    LOOP ;
diff --git a/blk/428 b/blk/428
index d97a8e0..a5093ca 100644
--- a/blk/428
+++ b/blk/428
@@ -10,7 +10,7 @@
     _s+crc _s+crc     ( a2 crc )
     SWAP 256 /MOD ROT ( h l crc )
     _s+crc _s+crc     ( crc )
-    0x01 OR           ( ensure stop bit )
+    1 OR              ( ensure stop bit )
     (spix) DROP       ( send CRC )
     _wait  ( wait for a valid response... )
 ;
diff --git a/blk/431 b/blk/431
index 748aa05..ef92fa1 100644
--- a/blk/431
+++ b/blk/431
@@ -1,16 +1,16 @@
 : SDC$
     10 0 DO _idle DROP LOOP
-    0 ( dummy ) 10 0 DO  ( r )
-        DROP 0x40 0 0 SDCMDR1  ( CMD0 )
-        DUP 0x01 = IF LEAVE THEN
-    LOOP 0x01 = NOT IF _err THEN
+    10 0 DO  ( r )
+        0x40 0 0 SDCMDR1  ( CMD0 )
+        DUP 1 = IF LEAVE ELSE DROP THEN
+    LOOP 1 = NOT IF _err THEN
     0x48 0 0x1aa ( CMD8 ) SDCMDR7 ( r arg1 arg2 )
-    0x1aa = NOT IF _err THEN      ( arg2 check )
-    0 = NOT IF _err THEN          ( arg1 check )
-    0x01 = NOT IF _err THEN       ( r check )
+    ( expected 1 0 0x1aa )
+    0x1aa = ROT ( arg1 f r ) 1 = AND SWAP ( f&f arg1 )
+    NOT ( 0 expected ) AND ( f&f&f ) NOT IF _err THEN
     BEGIN
         0x77 0 0 SDCMDR1  ( CMD55 )
-        0x01 = NOT IF _err THEN
-        0x69 0x4000 0x0000 SDCMDR1  ( CMD41 )
-        DUP 0x01 > IF _err THEN
+        1 = NOT IF _err THEN
+        0x69 0x4000 0 SDCMDR1  ( CMD41 )
+        DUP 1 > IF _err THEN
     NOT UNTIL ; ( out of idle mode, success! )
diff --git a/blk/432 b/blk/432
index fb7b9f0..3db170e 100644
--- a/blk/432
+++ b/blk/432
@@ -1,14 +1,14 @@
-: _sdc@  ( dstaddr blkno -- )
+: _  ( dstaddr blkno -- )
     [ SDC_DEVID LITN ] (spie)
     0x51 ( CMD17 ) 0 ROT ( a cmd 0 blkno ) _cmd
     IF _err THEN
     _wait 0xfe = NOT IF _err THEN
     0 SWAP               ( crc a )
     512 0 DO             ( crc a )
-        DUP _idle        ( crc a a n )
-        DUP ROT C!       ( crc a n )
-        ROT SWAP _crc16  ( a crc )
-        SWAP 1+          ( crc a+1 )
+        _idle            ( crc a n )
+        DUP ROT C!+      ( crc n a+1 )
+        ROT> _crc16      ( a+1 crc )
+        SWAP             ( crc a+1 )
     LOOP
     DROP                 ( crc1 )
     _idle 8 LSHIFT _idle +  ( crc2 )
diff --git a/blk/433 b/blk/433
index 15414d3..6bd635b 100644
--- a/blk/433
+++ b/blk/433
@@ -1,6 +1,4 @@
 : SDC@
-    2 * DUP BLK( SWAP    ( b a b )
-    _sdc@
-    1+ BLK( 512 + SWAP
-    _sdc@
+    2 * DUP BLK( SWAP ( b a b ) _
+    1+ BLK( 512 + SWAP _
 ;
diff --git a/blk/434 b/blk/434
index 6f74196..5f071a6 100644
--- a/blk/434
+++ b/blk/434
@@ -1,4 +1,4 @@
-: _sdc!  ( srcaddr blkno -- )
+: _  ( srcaddr blkno -- )
     [ SDC_DEVID LITN ] (spie)
     0x58 ( CMD24 ) 0 ROT ( a cmd 0 blkno ) _cmd
     IF _err THEN
diff --git a/blk/435 b/blk/435
index 7af62c9..f7828e9 100644
--- a/blk/435
+++ b/blk/435
@@ -1,6 +1,4 @@
 : SDC!
-    2 * DUP BLK( SWAP    ( b a b )
-    _sdc!
-    1+ BLK( 512 + SWAP
-    _sdc!
+    2 * DUP BLK( SWAP ( b a b ) _
+    1+ BLK( 512 + SWAP _
 ;