diff --git a/blk/580 b/blk/580
index b1b7b7f..3b21188 100644
--- a/blk/580
+++ b/blk/580
@@ -4,4 +4,5 @@ Support code for the RC2014 recipe. Contains drivers for the
 ACIA, SD card and AT28 EEPROM.
 
 581 ACIA                       590 AT28 EEPROM
-600 SD card                    618 Xcomp unit
+595 SPI relay                  600 SD card
+618 Xcomp unit
diff --git a/blk/595 b/blk/595
new file mode 100644
index 0000000..93f8d18
--- /dev/null
+++ b/blk/595
@@ -0,0 +1,12 @@
+SPI relay driver
+
+This driver is designed for a ad-hoc adapter card that acts as a
+SPI relay between the z80 bus and the SPI device. Sending any-  
+thing on SPI_CSLOW and SPI_CSHIGH is expected to select/deselect
+the device, and writing to SPI_DATA is expected to initiate a   
+byte exchange. The result of the exchange is excpected to be re-
+trieved by reading SPI_DATA.
+
+Provides (spie) (enable), (spid) (disable), (spix) (xchange).
+
+Load driver with "596 LOAD".
diff --git a/blk/596 b/blk/596
new file mode 100644
index 0000000..2fd9846
--- /dev/null
+++ b/blk/596
@@ -0,0 +1,12 @@
+CODE (spix) ( n -- n )
+    HL POP,
+    chkPS,
+    A L LDrr,
+    SPI_DATA OUTiA,
+    NOP, NOP, ( let SPI relay breathe )
+    SPI_DATA INAi,
+    L A LDrr,
+    HL PUSH,
+;CODE
+CODE (spie) SPI_CSLOW OUTiA, ;CODE
+CODE (spid) SPI_CSHIGH OUTiA, ;CODE
diff --git a/blk/600 b/blk/600
index 2d7374c..511e952 100644
--- a/blk/600
+++ b/blk/600
@@ -1,13 +1,11 @@
 SD Card driver
 
-Load range: 602-616
+Load range: 603-616
 
 This driver is designed for a ad-hoc adapter card that acts as a
-SPI relay between the z80 bus and the SD card. That adapter is  
-expected to pull CS low when something is written to SDC_CSLOW,
-high on SDC_CSHIGH and to initiate a SPI exchange when a byte is
-written to SDC_SPI, the result of that exchange being fetched   
-with a read to SDC_SPI.
+SPI relay between the z80 bus and the SD card. It requires a SPI
+driver providing (spix), (spie) and (spid), which oh surprise!
+is included in Collapse OS at B595.
 
-Through that layer, this driver implements the SDC protocol     
+Through that layer, this driver implements the SDC protocol
 allowing it to provide BLK@ and BLK!.
diff --git a/blk/602 b/blk/602
deleted file mode 100644
index 7fa35a9..0000000
--- a/blk/602
+++ /dev/null
@@ -1,12 +0,0 @@
-( Initiate SPI exchange with the SD card. n is the data to
-  send. )
-CODE _sdcSR  ( n -- n )
-    HL POP,
-    chkPS,
-    A L LDrr,
-    SDC_SPI OUTiA,
-    NOP, NOP,
-    SDC_SPI INAi,
-    L A LDrr,
-    HL PUSH,
-;CODE
diff --git a/blk/603 b/blk/603
index 554ff56..978520e 100644
--- a/blk/603
+++ b/blk/603
@@ -1,5 +1,3 @@
-CODE _sdcSel SDC_CSLOW OUTiA, ;CODE
-CODE _sdcDesel SDC_CSHIGH OUTiA, ;CODE
 ( Computes n into crc c with polynomial 0x1021 )
 CODE _crc16  ( c n -- c )
     HL POP, ( n ) DE POP, ( c )
diff --git a/blk/604 b/blk/604
index 0d34578..4537302 100644
--- a/blk/604
+++ b/blk/604
@@ -1,8 +1,8 @@
 ( -- n )
-: _idle 0xff _sdcSR ;
+: _idle 0xff (spix) ;
 
 ( -- n )
-( _sdcSR 0xff until the response is something else than 0xff
+( spix 0xff until the response is something else than 0xff
   for a maximum of 20 times. Returns 0xff if no response. )
 : _wait
     0  ( cnt )
diff --git a/blk/607 b/blk/607
index c9a4146..0d944fe 100644
--- a/blk/607
+++ b/blk/607
@@ -1,3 +1,3 @@
 ( send-and-crc7 )
 ( n c -- c )
-: _s+crc SWAP DUP _sdcSR DROP _crc7 ;
+: _s+crc SWAP DUP (spix) DROP _crc7 ;
diff --git a/blk/608 b/blk/608
index 3b252b3..d97a8e0 100644
--- a/blk/608
+++ b/blk/608
@@ -11,6 +11,6 @@
     SWAP 256 /MOD ROT ( h l crc )
     _s+crc _s+crc     ( crc )
     0x01 OR           ( ensure stop bit )
-    _sdcSR DROP       ( send CRC )
+    (spix) DROP       ( send CRC )
     _wait  ( wait for a valid response... )
 ;
diff --git a/blk/609 b/blk/609
index 885a3a7..1b89810 100644
--- a/blk/609
+++ b/blk/609
@@ -1,15 +1,15 @@
 ( cmd arg1 arg2 -- r )
 ( Send a command that expects a R1 response, handling CS. )
-: SDCMDR1 _sdcSel _cmd _sdcDesel ;
+: SDCMDR1 (spie) _cmd (spid) ;
 
 ( cmd arg1 arg2 -- r arg1 arg2 )
 ( Send a command that expects a R7 response, handling CS. A R7
   is a R1 followed by 4 bytes. arg1 contains bytes 0:1, arg2
   has 2:3 )
 : SDCMDR7
-    _sdcSel
+    (spie)
     _cmd                 ( r )
     _idle 8 LSHIFT _idle +  ( r arg1 )
     _idle 8 LSHIFT _idle +  ( r arg1 arg2 )
-    _sdcDesel
+    (spid)
 ;
diff --git a/blk/610 b/blk/610
index 12b7c44..8066197 100644
--- a/blk/610
+++ b/blk/610
@@ -1,4 +1,4 @@
-: _err _sdcDesel ABORT" SDerr" ;
+: _err (spid) ABORT" SDerr" ;
 
 ( Tight definition ahead, pre-comment.
 
diff --git a/blk/612 b/blk/612
index 134dd9d..b5799bf 100644
--- a/blk/612
+++ b/blk/612
@@ -1,5 +1,5 @@
 : _sdc@  ( dstaddr blkno -- )
-    _sdcSel 0x51 ( CMD17 ) 0 ROT ( a cmd 0 blkno ) _cmd
+    (spie) 0x51 ( CMD17 ) 0 ROT ( a cmd 0 blkno ) _cmd
     IF _err THEN
     _wait 0xfe = NOT IF _err THEN
     0 SWAP               ( crc a )
@@ -11,5 +11,5 @@
     LOOP
     DROP                 ( crc1 )
     _idle 8 LSHIFT _idle +  ( crc2 )
-    _wait DROP _sdcDesel
+    _wait DROP (spid)
     = NOT IF _err THEN ;
diff --git a/blk/614 b/blk/614
index 9123593..6d8aebf 100644
--- a/blk/614
+++ b/blk/614
@@ -1,16 +1,16 @@
 : _sdc!  ( srcaddr blkno -- )
-    _sdcSel 0x58 ( CMD24 ) 0 ROT ( a cmd 0 blkno ) _cmd
+    (spie) 0x58 ( CMD24 ) 0 ROT ( a cmd 0 blkno ) _cmd
     IF _err THEN
-    _idle DROP 0xfe _sdcSR DROP
+    _idle DROP 0xfe (spix) DROP
     0 SWAP           ( crc a )
     512 0 DO         ( crc a )
         C@+          ( crc a+1 n )
         ROT OVER     ( a n crc n )
         _crc16       ( a n crc )
         SWAP         ( a crc n )
-        _sdcSR DROP  ( a crc )
+        (spix) DROP  ( a crc )
         SWAP         ( crc a )
     LOOP
     DROP ( crc ) 256 /MOD ( lsb msb )
-    _sdcSR DROP _sdcSR DROP
-    _wait DROP _sdcDesel ;
+    (spix) DROP (spix) DROP
+    _wait DROP (spid) ;
diff --git a/blk/618 b/blk/618
index a0979c5..f0d294e 100644
--- a/blk/618
+++ b/blk/618
@@ -1,8 +1,6 @@
 0xff00 CONSTANT RS_ADDR        0xfffa CONSTANT PS_ADDR
 RS_ADDR 0x80 - CONSTANT SYSVARS
 0x8000 CONSTANT HERESTART
-4      CONSTANT SDC_SPI
-5      CONSTANT SDC_CSLOW      6      CONSTANT SDC_CSHIGH
 582 LOAD  ( acia decl )
 212 LOAD  ( z80 assembler )
 262 LOAD  ( xcomp )            282 LOAD  ( boot.z80.decl )
diff --git a/recipes/rc2014/sdcard/README.md b/recipes/rc2014/sdcard/README.md
index bfb8f56..d98f92a 100644
--- a/recipes/rc2014/sdcard/README.md
+++ b/recipes/rc2014/sdcard/README.md
@@ -71,11 +71,17 @@ instead.
 ## Building your binary
 
 The binary built in the base recipe doesn't have SDC drivers. Using the same
-instructions as in the `eeprom` recipe, you'll need to insert those drivers.
+instructions as in the `eeprom` recipe, you'll need to assemble a binary with
+those drivers. First, we need drivers for the SPI relay. This is done by
+declaring `SPI_DATA`, `SPI_CSLOW` and `SPI_CSHIGH`, which are respectively `4`,
+`5` and `6` in our relay design. You can then load the driver with `596 LOAD`.
+This driver provides `(spix)`, `(spie)` and `(spid)` which are then used in the
+SDC driver.
+
 The SDC driver is at B600. It gives you a load range. This means that what
 you need to insert in `xcomp` will look like:
 
-    602 616 LOADR  ( sdc )
+    603 616 LOADR  ( sdc )
 
 You also need to add `BLK$` to the init sequence.
 
@@ -104,7 +110,7 @@ If there is no error message, we're fine. Then, we need to hook `BLK@*` and
 
 And thats it! You have full access to disk block mechanism:
 
-    102 LOAD
+    105 LOAD
     BROWSE
 
 (at this moment, the driver is a bit slow though...)