diff --git a/Kernel/platform/platform-rcbus-z8/Makefile b/Kernel/platform/platform-rcbus-z8/Makefile
index 7006602b72..94d11fd632 100644
--- a/Kernel/platform/platform-rcbus-z8/Makefile
+++ b/Kernel/platform/platform-rcbus-z8/Makefile
@@ -47,7 +47,7 @@ clean:
 	rm -f $(OBJS) $(JUNK)  core *~ bootblock.bin bootblock fuzix.bin loader.tmp
 
 image: 
-	$(CROSS_LD) -t -b -C 0x0100 -S 0xF000 -f CLDBbXSs -o fuzix.bin crt0.o devices.o main.o \
+	$(CROSS_LD) -b -C 0x0100 -D 0x0100 -S 0xF000 -f CLDBbXSs -o fuzix.bin crt0.o devices.o main.o \
 	discard.o commonmem.o tricks.o rcbus-z8.o devtty.o \
 	../../start.o ../../version.o ../../cpu-z8/lowlevel-z8.o \
 	../../mm/bankfixed.o ../../timer.o ../../kdata.o  ../../mm/memalloc_none.o \
diff --git a/Kernel/platform/platform-rcbus-z8/config.h b/Kernel/platform/platform-rcbus-z8/config.h
index 150e77f397..bb01d2674c 100644
--- a/Kernel/platform/platform-rcbus-z8/config.h
+++ b/Kernel/platform/platform-rcbus-z8/config.h
@@ -18,6 +18,7 @@
 #define MAP_SIZE	0x8000U
 
 #define CONFIG_TD_NUM	1
+#define CONFIG_TD_SD
 #define TD_SD_NUM	1
 
 /* Read processes and big I/O direct into process space */
diff --git a/Kernel/platform/platform-rcbus-z8/kernel.def b/Kernel/platform/platform-rcbus-z8/kernel.def
index 8b003a0c8c..f8cc1b575e 100644
--- a/Kernel/platform/platform-rcbus-z8/kernel.def
+++ b/Kernel/platform/platform-rcbus-z8/kernel.def
@@ -8,3 +8,7 @@ PROGBASE		    .equ 0x0000
 PROGLOAD		    .equ 0x0100
 
 CONFIG_SWAP		    .equ 1
+
+
+MAINBANK		    .equ 0x10
+INTBANK			    .equ 0x20
diff --git a/Kernel/platform/platform-rcbus-z8/main.c b/Kernel/platform/platform-rcbus-z8/main.c
index 18267dd208..d02c170e82 100644
--- a/Kernel/platform/platform-rcbus-z8/main.c
+++ b/Kernel/platform/platform-rcbus-z8/main.c
@@ -22,4 +22,9 @@ void plt_interrupt(void)
  timer_interrupt();
 }
 
+void plt_reinterrupt(void)
+{
+ tty_pollirq();
+}
+
 /* Nothing to do for the map of init */
diff --git a/Kernel/platform/platform-rcbus-z8/rcbus-z8.S b/Kernel/platform/platform-rcbus-z8/rcbus-z8.S
index 88a10d25a2..de269b7fee 100644
--- a/Kernel/platform/platform-rcbus-z8/rcbus-z8.S
+++ b/Kernel/platform/platform-rcbus-z8/rcbus-z8.S
@@ -21,14 +21,17 @@ plt_interrupt_all:
 
 	.export _int_disabled
 	.export _mem_bank
+	.export istack_switched_sp
 
 	.org 8
 _int_disabled:
 	.byte 0
 _mem_bank:
 	.byte 0
-_saved_bank:
+_mem_saved_bank:
 	.byte 0
+istack_switched_sp:
+	.word 0
 
 	.code
 
@@ -115,6 +118,7 @@ map_proc_di:
 	jr nz, map_notk
 	or r15,r15
 	jr z, map_kernel
+map_notk:
 	push r3
 	lde r3,@rr14
 	ld _mem_bank,r3
@@ -157,12 +161,23 @@ outchw:
 ;
 ;	Bitbang SPI : TODO
 ;
-	.export _z8_spi_tx
-_z8_spi_tx:
-	ret
-
-	.export _z8_spi_rx
-_z8_spi_rx:
+	.export _sd_spi_tx_byte
+	.export _sd_spi_rx_byte
+	.export _sd_spi_tx_sector
+	.export _sd_spi_rx_sector
+	.export _sd_spi_lower_cs
+	.export _sd_spi_raise_cs
+	.export _sd_spi_fast
+	.export _sd_spi_slow
+
+_sd_spi_tx_byte:
+_sd_spi_rx_byte:
+_sd_spi_tx_sector:
+_sd_spi_rx_sector:
+_sd_spi_lower_cs:
+_sd_spi_raise_cs:
+_sd_spi_fast:
+_sd_spi_slow:
 	ret
 
 ;
@@ -204,7 +219,7 @@ has_ch:
 	.export _z8tty_put
 _z8tty_put:
 	ld r3,#2
-	call __garg2
+	call __gargr2
 	ld 0xF0,r3
 	ret
 
diff --git a/Kernel/platform/platform-rcbus-z8/tricks.S b/Kernel/platform/platform-rcbus-z8/tricks.S
index dd94a6038f..b9457862d8 100644
--- a/Kernel/platform/platform-rcbus-z8/tricks.S
+++ b/Kernel/platform/platform-rcbus-z8/tricks.S
@@ -29,8 +29,8 @@ _plt_switchout:
 	incw rr14
 	lde @rr14,r3
 	call map_proc_always
-	ld r14,#>__udata
-	ld r15,#<__udata
+	ld r14,#>_udata
+	ld r15,#<_udata
 	ld r12,#>U_DATA_STASH
 	ld r13,#<U_DATA_STASH
 	clr r0
@@ -77,14 +77,14 @@ _switchin:
 	jr nz, copyback
 	sub r1,r15
 	jr z, skip_copyback
-copybank:
+copyback:
 	; Map process r3
 	call map_proc_a
 
 	push r14
 	push r15
-	ld r14,#>__udata
-	ld r15,#<__udata
+	ld r14,#>_udata
+	ld r15,#<_udata
 	ld r12,#>U_DATA_STASH
 	ld r13,#<U_DATA_STASH
 	clr r0
@@ -165,7 +165,7 @@ skip_copyback:
 in_isr:
 	ret
 
-switchfal:
+switchfail:
 	call outr14
 	ld r14,#>badswitchmsg
 	ld r15,#<badswitchmsg
@@ -223,7 +223,7 @@ copy48K:
 
 _dofork:
 	ld r15,#2
-	call __garg2
+	call __gargr2
 
 	ld r14,r2
 	ld r15,r3
@@ -263,7 +263,7 @@ _dofork:
 	ld r13,#<U_DATA__U_PAGE
 	lde r1,@rr12	; source
 
-	call copy48k
+	call copy48K
 
 	call map_proc_always
 
@@ -273,8 +273,8 @@ _dofork:
 	push r15
 
 	; udata to parent stash
-	ld r14,#>__udata
-	ld r15,#<__udata
+	ld r14,#>_udata
+	ld r15,#<_udata
 	ld r12,#>U_DATA_STASH
 	ld r13,#<U_DATA_STASH
 	clr r0
@@ -321,3 +321,7 @@ l2:
 
 _need_resched:
 	.byte	0
+
+badswitchmsg:
+	.ascii	"badswitch"
+	.byte	0