I just ordered a used Sphairon Turbolink AR860 ADSL2+ modem/router, because I'm fed up with the TR69 remote-controlled bluetooth dect wlan kitchen-sink-appliances they sell as DSL routers these days.
Those might be great as honeypots if you're looking to get hacked, but this is not my goal.
However, I couldn't find any firmware online for this device, and the company is bust.
And I didn't catch that the modem has Annex B support only (which makes sense for it's age), but I'm on an Annex J line.
Now AFAIK, Annex B modems can usually be made Annex J compatible with a firmware upgrade. Correct me if I'm wrong.
But as I mentioned, the company is bust, so no dice. Until I found your awesome RouterTech aftermarket firmware here?
I don't have the device yet, but from this report here, the device works with this firmware:
This tells me it's based on the TI-AR7, and from some datasheet-googling, I found that chipset support for Annex J seems to exist (https://www.ti.com/pdfs/vf/bband/ar7_nsp_prod_brief.pdf).routertech_ar7rd_pspboot_1port_firmware_20081123_140.zip
So here is the big question I couldn't answer yet: Does the RouterTech firmware support Annex J?
The last release was in 2012, and Annex J is not that old, so I'm unsure.
The firmware download is broken, and I can't really search the forum for "Annex J" either, because it will just ignore the J.
I know time has moved on, but I hope the source-code gurus are still around!