diff --git a/src/m515Bus.h b/src/m515Bus.h
index f6e3eda..8a31c43 100644
--- a/src/m515Bus.h
+++ b/src/m515Bus.h
@@ -11,7 +11,7 @@
 #define DBVZ_END_BANK(address, size) (DBVZ_START_BANK(address) + DBVZ_NUM_BANKS(size) - 1)
 #define DBVZ_BANK_IN_RANGE(bank, address, size) ((bank) >= DBVZ_START_BANK(address) && (bank) <= DBVZ_END_BANK(address, size))
 #define DBVZ_BANK_ADDRESS(bank) ((bank) << DBVZ_BANK_SCOOT)
-#define DBVZ_TOTAL_MEMORY_BANKS (1 << (32 - DBVZ_BANK_SCOOT))//0x40000 banks for BANK_SCOOT = 14
+#define DBVZ_TOTAL_MEMORY_BANKS (1 << (32 - DBVZ_BANK_SCOOT))//0x40000 banks for *_BANK_SCOOT = 14
 
 //chip addresses and sizes
 //after boot RAM is at 0x00000000,
diff --git a/src/pxa255/pxa255.c b/src/pxa255/pxa255.c
index 9c29c86..92a633a 100644
--- a/src/pxa255/pxa255.c
+++ b/src/pxa255/pxa255.c
@@ -81,10 +81,10 @@ bool pxa255Init(uint8_t** returnRom, uint8_t** returnRam){
 
    //CPU registers
    mem_areas[2].base = PXA255_REG_START_ADDRESS;
-   mem_areas[2].size = PXA255_REG_SIZE;
+   mem_areas[2].size = 0x40000000;//size of address space, not all of it is mapped
    mem_areas[2].ptr = NULL;
 
-   for(i = 0; i < 64; i++){
+   for(i = 0; i < PXA255_TOTAL_MEMORY_BANKS; i++){
        // will fallback to bad_* on non-memory addresses
        read_byte_map[i] = memory_read_byte;
        read_half_map[i] = memory_read_half;
@@ -94,12 +94,15 @@ bool pxa255Init(uint8_t** returnRom, uint8_t** returnRam){
        write_word_map[i] = memory_write_word;
    }
 
-   read_byte_map[PXA255_START_BANK(PXA255_REG_START_ADDRESS)] = pxa255_read_byte;
-   read_half_map[PXA255_START_BANK(PXA255_REG_START_ADDRESS)] = pxa255_read_half;
-   read_word_map[PXA255_START_BANK(PXA255_REG_START_ADDRESS)] = pxa255_read_word;
-   write_byte_map[PXA255_START_BANK(PXA255_REG_START_ADDRESS)] = pxa255_write_byte;
-   write_half_map[PXA255_START_BANK(PXA255_REG_START_ADDRESS)] = pxa255_write_half;
-   write_word_map[PXA255_START_BANK(PXA255_REG_START_ADDRESS)] = pxa255_write_word;
+   //add PXA255 register range
+   for(i = PXA255_START_BANK(PXA255_REG_START_ADDRESS); i <= PXA255_END_BANK(PXA255_REG_START_ADDRESS, mem_areas[2].size); i++){
+      read_byte_map[i] = pxa255_read_byte;
+      read_half_map[i] = pxa255_read_half;
+      read_word_map[i] = pxa255_read_word;
+      write_byte_map[i] = pxa255_write_byte;
+      write_half_map[i] = pxa255_write_half;
+      write_word_map[i] = pxa255_write_word;
+   }
 
    //set up CPU hardware
    pxa255icInit(&tungstenCIc);
@@ -170,6 +173,12 @@ void pxa255LoadState(uint8_t* data){
 }
 
 void pxa255Execute(void){
+#if OS_HAS_PAGEFAULT_HANDLER
+    os_exception_frame_t seh_frame = { NULL, NULL };
+
+    os_faulthandler_arm(&seh_frame);
+#endif
+
    //TODO: need to set cycle_count_delta with the amout of opcodes to run
    cycle_count_delta = -500;//just a test value
 
@@ -202,6 +211,10 @@ void pxa255Execute(void){
              cpu_arm_loop();
     }
 
+#if OS_HAS_PAGEFAULT_HANDLER
+    os_faulthandler_unarm(&seh_frame);
+#endif
+
     //render
     pxa255lcdFrame(&tungstenCLcd);
 }
diff --git a/src/tungstenCBus.h b/src/tungstenCBus.h
index 7df1c6a..8692a7d 100644
--- a/src/tungstenCBus.h
+++ b/src/tungstenCBus.h
@@ -4,13 +4,16 @@
 #define PXA255_ROM_START_ADDRESS 0x00000000
 #define PXA255_RAM_START_ADDRESS 0xA0000000
 #define PXA255_REG_START_ADDRESS 0x40000000
-#define TUNGSTEN_C_ROM_SIZE (4 * 0x100000)//4mb ROM
+#define TUNGSTEN_C_ROM_SIZE (10 * 0x100000)//10mb ROM
 #define TUNGSTEN_C_RAM_SIZE (64 * 0x100000)//64mb RAM
-#define PXA255_REG_SIZE 0x40000000
 
 #define PXA255_BANK_SCOOT 26
-#define PXA255_START_BANK(address) ((address) >> PXA255_BANK_SCOOT)
 #define PXA255_NUM_BANKS(areaSize) (((areaSize) >> PXA255_BANK_SCOOT) + ((areaSize) & ((1 << PXA255_BANK_SCOOT) - 1) ? 1 : 0))
+#define PXA255_START_BANK(address) ((address) >> PXA255_BANK_SCOOT)
+#define PXA255_END_BANK(address, size) (PXA255_START_BANK(address) + PXA255_NUM_BANKS(size) - 1)
+#define PXA255_BANK_IN_RANGE(bank, address, size) ((bank) >= PXA255_START_BANK(address) && (bank) <= PXA255_END_BANK(address, size))
+#define PXA255_BANK_ADDRESS(bank) ((bank) << PXA255_BANK_SCOOT)
+#define PXA255_TOTAL_MEMORY_BANKS (1 << (32 - PXA255_BANK_SCOOT))//64 banks for *_BANK_SCOOT = 26
 
 
 #endif