diff --git a/MCUME_pico2/flash/flash_t.c b/MCUME_pico2/flash/flash_t.c
index 0510398..fda43d7 100644
--- a/MCUME_pico2/flash/flash_t.c
+++ b/MCUME_pico2/flash/flash_t.c
@@ -10,24 +10,51 @@
 #include "hardware/sync.h"
 #include "emuapi.h"
 
+extern size_t _psram_size;
+
+static bool using_psram;
+
+#define PSRAM_BASE (0x11000000)
+// #define PSRAM_BASE (0x15000000) // there's no reason to use uncached access
 
 unsigned char * flash_start = (unsigned char *)(XIP_BASE + HW_FLASH_STORAGE_BASE);
 unsigned char * flash_end = (unsigned char *)(XIP_BASE + HW_FLASH_STORAGE_TOP);
 
 static uint8_t cache[FLASH_SECTOR_SIZE];
 
-int flash_load(const char * filename) 
+static void flash_setup() {
+    if (_psram_size) {
+        using_psram = true;
+        flash_start = (unsigned char*)PSRAM_BASE;
+        flash_end = flash_start + _psram_size;
+    } else {
+        using_psram = false;
+    }
+}
+
+int flash_load_common(const char * filename, bool do_bswap)
 {
-  uint32_t offset = HW_FLASH_STORAGE_BASE;
+  flash_setup();
+
+  uint8_t *dest = flash_start;
   int n;
   int size = 0;
   emu_printf("flash_load...");
   int f = emu_FileOpen(filename,"r+b");
   if (f) {
-    while ( (offset < (HW_FLASH_STORAGE_TOP-FLASH_SECTOR_SIZE)) && (n = emu_FileRead(cache,FLASH_SECTOR_SIZE,f) ) ) {
-      //memcpy(cache, (unsigned char *)offset, n);
-      if (memcmp(cache, (unsigned char*)XIP_BASE + offset, n)) {
+    while ( (dest < (flash_end-FLASH_SECTOR_SIZE)) && (n = emu_FileRead(cache,FLASH_SECTOR_SIZE,f) ) ) {
+      if (do_bswap) {
+          for (int i=0;i<n; i+=2) {
+              uint8_t k = cache[i];
+              cache[i]=cache[i+1];
+              cache[i+1] = k;
+          }
+      }
+      if (using_psram) {
+          memcpy(dest, cache, n);
+      } else if (memcmp(cache, dest, n)) {
           uint32_t ints = save_and_disable_interrupts();
+          uint32_t offset = dest - (uint8_t*)XIP_BASE;
           flash_range_erase(offset, FLASH_SECTOR_SIZE);
           flash_range_program(offset, (const uint8_t *)&cache[0], FLASH_SECTOR_SIZE);
           restore_interrupts(ints);
@@ -39,7 +66,7 @@ int flash_load(const char * filename)
           //emu_printi(pt[2]);
           //emu_printi(pt[3]);
       }
-      offset += FLASH_SECTOR_SIZE;
+      dest += FLASH_SECTOR_SIZE;
       size += n;          
     }
     emu_FileClose(f);
@@ -49,45 +76,20 @@ int flash_load(const char * filename)
   return size;
 }
 
-int flash_load_bswap(const char * filename) 
+int flash_load(const char * filename)
 {
-  uint32_t offset = HW_FLASH_STORAGE_BASE;
-  int n;
-  int size = 0;
-  emu_printf("flash_load...");
-  int f = emu_FileOpen(filename,"r+b");
-  if (f) {
-    while ( (offset < (HW_FLASH_STORAGE_TOP-FLASH_SECTOR_SIZE)) && (n = emu_FileRead(cache,FLASH_SECTOR_SIZE,f) ) ) {
-      for (int i=0;i<n; i+=2) {
-        uint8_t k = cache[i];
-        cache[i]=cache[i+1];
-        cache[i+1] = k;
-      }  
-      //memcpy(cache, (unsigned char *)offset, n);
-      uint32_t ints = save_and_disable_interrupts();   
-      flash_range_erase(offset, FLASH_SECTOR_SIZE);
-      flash_range_program(offset, (const uint8_t *)&cache[0], FLASH_SECTOR_SIZE);
-      restore_interrupts(ints);      
-      emu_printi(n);
-      emu_printi(offset);          
-      //uint8_t * pt = (uint8_t*)(XIP_BASE + offset);
-      //emu_printi(pt[0]);
-      //emu_printi(pt[1]);
-      //emu_printi(pt[2]);
-      //emu_printi(pt[3]);
-      offset += FLASH_SECTOR_SIZE;
-      size += n;          
-    }
-    emu_FileClose(f);
-    emu_printf("flash_load OK.");    
-  }
+    return flash_load_common(filename, false);
+}
 
-  return size;
+int flash_load_bswap(const char * filename)
+{
+    return flash_load_common(filename, true);
 }
 
 int flash_verify(unsigned char * buf, int size)
 {
-  unsigned char * datapt = (unsigned char *)(XIP_BASE + HW_FLASH_STORAGE_BASE);
+  flash_setup();
+  unsigned char * datapt = flash_start;
   emu_printf("flash_verify...");
   int count = size;
   while (count++ < size) {