I had a card showed in the cardinfo, but not working at all (at least no on my Miggy), but work ok on my laptop.
If the card worked once the Amiga, and showed at early startup (or in cardinfo), the logic is ok. But in the other side it could be broken somewhere: RJ45 dongle/adapter, bad cable, bad ADSL modem...
The inexpensive way to fix it is buying another cable (or crimping another one), then buying another modem.
Just put the suspect devices in other machine (one at a time) will show where the problem is.
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BTW: the second card is listed as compatible in cnet.device list?
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Silly me. The card IS in cnet.device list. But with a little "glitch" in the behavior.
A good point is install the new version of cnet.device (1.9) from
aminet.