diff --git a/isd1200.c b/isd1200.c
index efc4523..501b695 100644
--- a/isd1200.c
+++ b/isd1200.c
@@ -152,7 +152,9 @@ void isd1200_flash_read(uint32_t page, uint8_t *buffer)
 
 	uint32_t offset = page * 512;
 
-	*(uint32_t *)&buf[1] = __builtin_bswap32(offset << 8);
+	buf[1] = (offset >> 16) & 0xFF;
+	buf[2] = (offset >> 8) & 0xFF;
+	buf[3] = offset & 0xFF;
 
 	nuvoton_spi_transfer(buf, sizeof(buf));
 
@@ -175,7 +177,9 @@ void isd1200_flash_write(uint32_t page, uint8_t *buffer)
 
 	uint32_t offset = page * 16;
 
-	*(uint32_t *)&buf[1] = __builtin_bswap32(offset << 8);
+	buf[1] = (offset >> 16) & 0xFF;
+	buf[2] = (offset >> 8) & 0xFF;
+	buf[3] = offset & 0xFF;
 
 	memcpy(&buf[4], buffer, 16);
 
diff --git a/spi.pio b/spi.pio
index f3976d2..663ebc7 100644
--- a/spi.pio
+++ b/spi.pio
@@ -74,7 +74,7 @@ bitloop:
     out pins, 1        side 0x2
     mov x, y           side 0x2
     in pins, 1         side 0x0
-    jmp !osre byteloop  side 0x0
+    jmp !osre byteloop  side 0x0 [31]
 
 public entry_point:                 ; Must set X,Y to n-2 before starting!
     pull ifempty       side 0x1 [1] ; Block with CSn high (minimum 2 cycles)