Excellent work. Thanks a lot.
I am following the instructions I flashed my Speedport W 504V from windows 8.1. USB to serial converter (PL2303), putty extra and his x modem well completed the task. After a reboot everything works well, lan port, wi fi, luci… Especially I tested continuously for 15 days in acsess point and client bridge (repeater) mode. I did not notice any problem or need to reboot. Router is working very stable. The test is repeated in both band 2.4/5 GHz and I observed a slightly weaker signal at 5 GHz. But It is in accordance with IEEE recommendation.
I have not tested the ADSL connection.
Finally, I reopened my router and I soldered directly to pcb, two pigtail cable with external RP SMA connector. Signal is much stronger and increased overall throughput. Excellent properties for LNA/PA chip SiGe 2593 –A20. Also I noticed inside that is hot pin of internal U. FL connectors interrupted toward rest of pcb.
This flash has breathed new life into my not so old router.