HowToFlash.txt: update doc

Author: dingo35

SmartEVSE-3/HowToFlash.txt

@@ -1,5 +1,4 @@
 -surf to http://your-smartevse/update
--select the firmware.bin from this archive, OR if you want the debug version (via telnet over your wifi),
- rename firmware.debug.bin to firmware.bin and select that. YOU CANNOT FLASH A FILE WITH ANOTHER NAME!
+-select the firmware.bin from this archive, OR if you want the debug version (via telnet over your wifi), select firmware.debug.bin; select the "signed" versions if you want to be sure you are flashing an original factory or dingo35 version
 -if you get FAIL, check your wifi connection and try again;
 -after OK, wait 10-30 seconds and your new firmware including the webserver should be online!