diff --git a/src/system/boot/platform/atari_m68k/atari_memory_map.h b/src/system/boot/platform/atari_m68k/atari_memory_map.h
index b8b9000ac9..881450a898 100644
--- a/src/system/boot/platform/atari_m68k/atari_memory_map.h
+++ b/src/system/boot/platform/atari_m68k/atari_memory_map.h
@@ -5,25 +5,70 @@
 #ifndef ATARI_MEMORY_MAP_H
 #define ATARI_MEMORY_MAP_H
 
-#define ATARI_CHIPRAM_TOP_TT		0x00a00000
-/* -> e00000 is VME for MegaST*/
-#define ATARI_CHIPRAM_TOP_FALCON	0x00e00000
+/* the DMA-accessible RAM */
+#define ATARI_CHIPRAM_BASE			0x00000000
+#define ATARI_CHIPRAM_MAX			0x00e00000
+#define ATARI_CHIPRAM_LAST						\
+	(ATARI_CHIPRAM_BASE + (ATARI_CHIPRAM_MAX - 1))
 
-#define ATARI_ROM_BASE				ATARI_CHIPRAM_TOP_FALCON
-#define ATARI_ROM_TOP				0x00f00000
-#define ATARI_IO_BASE				ATARI_ROM_TOP
-#define 	ATARI_CARTRIDGE_BASE	0x00fa0000
-#define 	ATARI_OLD_ROM_BASE		0x00fc0000
+#define ATARI_TOSROM_BASE			0x00e00000
+#define ATARI_TOSROM_MAX			0x00100000
+#define ATARI_TOSROM_LAST						\
+	(ATARI_TOSROM_BASE + (ATARI_TOSROM_MAX - 1))
 
-#define ATARI_IO_TOP				0x01000000
-#define ATARI_FASTRAM_TOP			ATARI_IO_TOP
+/* some reserved ST I/O there... */
 
+/* cartridge ROM */
+#define ATARI_CARTROM_BASE			0x00fa0000
+#define ATARI_CARTROM_MAX			0x00020000
+#define ATARI_CARTROM_LAST						\
+	(ATARI_CARTROM_BASE + (ATARI_CARTROM_MAX - 1))
+
+#define ATARI_SYSROM_BASE			0x00fc0000
+#define ATARI_SYSROM_MAX			0x00030000
+#define ATARI_SYSROM_LAST						\
+	(ATARI_SYSROM_BASE + (ATARI_SYSROM_MAX - 1))
+
+/* more ST I/O there... */
+
+/* the fast, non-DMA-accessible RAM */
+#define ATARI_FASTRAM_BASE			0x01000000
+// max on TT,
+// but there is nothing beyond until SHADOW_BASE
+//#define ATARI_FASTRAM_MAX			0x00400000
+#define ATARI_FASTRAM_MAX			0xfe000000
+#define ATARI_FASTRAM_LAST						\
+	(ATARI_FASTRAM_BASE + (ATARI_FASTRAM_MAX - 1))
+
+
+
+/* due to ST legacy (24 bit addressing), IO is actually there */
 #define ATARI_SHADOW_BASE			0xff000000
 
-/* how we will use it */
+#define ATARI_IO_BASE				(ATARI_SHADOW_BASE + 0x00f00000)
+#define ATARI_IO_MAX				0x00100000
+#define ATARI_IO_LAST							\
+	(ATARI_IO_BASE + (ATARI_IO_MAX - 1))
+
+
+
+
+
+/* physical memory layout as used by the bootloader */
+
 //#define ATARI_ZBEOS_STACK_BASE		0x00040000
 #define ATARI_ZBEOS_STACK_BASE		0x00060000
 #define ATARI_ZBEOS_STACK_END		0x00080000
-#define ATARI_ZBEOS_BASE			0x00080000 /* from .prg shell.S will copy itself there */
+
+/* from .prg shell.S will copy itself there
+ * must stay in sync with src/system/ldscripts/m68k/boot_prg_atari_m68k.ld
+ */
+#define ATARI_ZBEOS_BASE			0x00080000
+#define ATARI_ZBEOS_MAX				0x00080000
+#define ATARI_ZBEOS_LAST						\
+	(ATARI_ZBEOS_BASE + (ATARI_ZBEOS_MAX - 1))
+
+
+#define ATARI_STRAM_VIRT_BASE		
 
 #endif	/* ATARI_MEMORY_MAP_H */
diff --git a/src/system/boot/platform/atari_m68k/mmu.cpp b/src/system/boot/platform/atari_m68k/mmu.cpp
index bf25150a3c..c62c38f1a9 100644
--- a/src/system/boot/platform/atari_m68k/mmu.cpp
+++ b/src/system/boot/platform/atari_m68k/mmu.cpp
@@ -6,6 +6,7 @@
  */
 
 
+#include "atari_memory_map.h"
 #include "mmu.h"
 
 #include <boot/platform.h>
@@ -46,20 +47,14 @@
 /** The (physical) memory layout of the boot loader is currently as follows:
  *	  0x0800 - 0x10000	supervisor mode stack (1) XXX: more ? x86 starts at 500
  *	 0x10000 - ?		code (up to ~500 kB)
- *	unused (TT0 instead):
- *	 0x90000			1st temporary page table (identity maps 0-4 MB)
- *	 0x91000			2nd (4-8 MB)
- *
- *	 0x92000 - 0x92000	further page tables
- *	0x100000			page directory
+ *  0x100000 or FAST_RAM_BASE if any:
+ *	     ...			page directory
  *	     ...			boot loader heap (32 kB)
  *	     ...			free physical memory
- *	[0xa00000]			end of chip RAM for TT (falcon has more till ROM)
- *	[0xe00000 - 0xf00000	TOS ROM]
- *	[0xf00000 - 0x1000000	I/O]
- XXX: where is the video buffer ?
+ *  0xdNNNNN			video buffer usually there, as per v_bas_ad
+ *						(=Logbase() but Physbase() is better)
  *
- *	The first 16 MB (2) are identity mapped (0x0 - 0x1000000); paging 
+ *	The first 32 MB (2) are identity mapped (0x0 - 0x1000000); paging 
  *	is turned on. The kernel is mapped at 0x80000000, all other stuff 
  *	mapped by the loader (kernel args, modules, driver settings, ...) 
  *	comes after 0x81000000 which means that there is currently only 
@@ -67,9 +62,10 @@
  *	
  *	(1) no need for user stack, we are already in supervisor mode in the
  *	loader.
- *	(2) maps the whole regular ST space; transparent translation registers 
- *	have larger granularity anyway;
+ *	(2) maps the whole regular ST space; transparent translation registers
+ *	have larger granularity anyway.
  */
+#warning M68K: check for Physbase() < ST_RAM_TOP
 
 #define TRACE_MMU
 #ifdef TRACE_MMU
@@ -444,7 +440,8 @@ mmu_init_for_kernel(void)
 
 
 	// remove identity mapping of ST space
-	gMMUOps->set_tt(0, NULL, 0, 0);
+	// actually done by the kernel when it's done using query_early
+	//gMMUOps->set_tt(0, NULL, 0, 0);
 
 #if 0
 	// set up a new idt
@@ -594,6 +591,11 @@ mmu_init(void)
 	gKernelArgs.num_physical_allocated_ranges = 1;
 		// remember the start of the allocated physical pages
 
+	// enable transparent translation of the first 32 MB
+	gMMUOps->set_tt(0, ATARI_CHIPRAM_BASE, 0x02000000, 0);
+	// enable transparent translation of the 16MB ST shadow range for I/O
+	gMMUOps->set_tt(0, ATARI_SHADOW_BASE, 0x01000000, 0);
+
 	init_page_directory();
 #if 0
 
diff --git a/src/system/boot/platform/atari_m68k/mmu_030.cpp b/src/system/boot/platform/atari_m68k/mmu_030.cpp
index b282fb5b6b..8ac4e4e6fd 100644
--- a/src/system/boot/platform/atari_m68k/mmu_030.cpp
+++ b/src/system/boot/platform/atari_m68k/mmu_030.cpp
@@ -45,20 +45,20 @@ initialize(void)
 static status_t
 set_tt(int which, addr_t pa, size_t len, uint32 perms)
 {
-	TRACE(("mmu_030:set_tt(%d, 0x%lx, %ld, 0x%08lx)\n", which, pa, len, perms));
+	TRACE(("mmu_030:set_tt(%d, 0x%lx, 0x%lx, 0x%08lx)\n", which, pa, len, perms));
 	uint32 mask;
 	uint32 ttr = 0;
-	mask = 1;
+	mask = 0x0000ffff;
 	if (len) {
+		len = (len >> 24) & 0x00ff;
 		while (len >>= 1)
 			mask <<= 1;
-		mask = (mask - 1);
 		// enable, cachable(?), r/w
 		// super only
 		// mc68030 user's manual, page 9-57
 		ttr = 0x08043;
 		ttr |= (pa & 0xff000000);
-		ttr |= ((mask & 0xff000000) >> 8);
+		ttr |= (mask & 0x00ff0000);
 	}
 	TRACE(("mmu_030:set_tt: 0x%08lx\n", ttr));
 	
diff --git a/src/system/boot/platform/atari_m68k/mmu_040.cpp b/src/system/boot/platform/atari_m68k/mmu_040.cpp
index 98b2cf7c2d..ae307d91db 100644
--- a/src/system/boot/platform/atari_m68k/mmu_040.cpp
+++ b/src/system/boot/platform/atari_m68k/mmu_040.cpp
@@ -43,21 +43,21 @@ initialize(void)
 
 
 static status_t
-set_tt(int which, addr_t pa, size_t len, uint32 perms)
+set_tt(int which, addr_t pa, size_t len, uint32 perms /* NOTUSED */)
 {
-	TRACE(("mmu_040:set_tt(%d, 0x%lx, %ld, 0x%08lx)\n", which, pa, len, perms));
+	TRACE(("mmu_040:set_tt(%d, 0x%lx, 0x%lx, 0x%08lx)\n", which, pa, len, perms));
 	uint32 mask;
 	uint32 ttr = 0;
-	mask = 1;
+	mask = 0x0000ffff;
 	if (len) {
+		len = (len >> 24) & 0x00ff;
 		while (len >>= 1)
 			mask <<= 1;
-		mask = (mask - 1);
 		// enable, super only, upa=0,
 		// cachable write-through, rw
 		ttr = 0x0a000;
 		ttr |= (pa & 0xff000000);
-		ttr |= ((mask & 0xff000000) >> 8);
+		ttr |= (mask & 0x00ff0000);
 	}
 	TRACE(("mmu_040:set_tt: 0x%08lx\n", ttr));
 	
diff --git a/src/system/boot/platform/atari_m68k/start.c b/src/system/boot/platform/atari_m68k/start.c
index f03b1ba13c..a05109dc04 100644
--- a/src/system/boot/platform/atari_m68k/start.c
+++ b/src/system/boot/platform/atari_m68k/start.c
@@ -123,11 +123,16 @@ _start(void)
 	init_nat_features();
 
 	//serial_init();
-	console_init();
 	Bconout(DEV_CON, 'K');
-	cpu_init();
+	console_init();
 	Bconout(DEV_CON, 'U');
-	//mmu_init();
+	dprintf("membot  = %p\n", *TOSVAR_membot);
+	dprintf("memtop  = %p\n", *TOSVAR_memtop);
+	dprintf("v_bas_ad= %p\n", *TOSVAR_v_bas_ad);
+	dprintf("phystop = %p\n", *TOSVARphystop);
+	dprintf("ramtop  = %p\n", *TOSVARramtop);
+	cpu_init();
+	mmu_init();
 
 	// wait a bit to give the user the opportunity to press a key
 	spin(750000);