bugfix map detect, configurable work address

src/fileops.c

@@ -41,6 +41,9 @@ UINT file_write() {
 UINT file_readblock(void* buf, uint32_t addr, uint16_t size) {
 	UINT bytes_read;
 	file_res = f_lseek(&file_handle, addr);
+	if(file_handle.fptr != addr) {
+		return 0;
+	}
 	if(file_res) { dprintf("no lseek %d\n", file_res); _delay_ms(30); return 0;}
 	file_res = f_read(&file_handle, buf, size, &bytes_read);
 	if(file_res) { dprintf("no read %d\n", file_res); _delay_ms(30); }