The uiptask hangs while trying to configure the (apparently old) phy. In particular it reads the phy ID registers, gets 65535 (all ones), then exits with an error. The task then retries.
Investigating further, the model of phy IC changed. Version 1 of the PCB defines a national part, version 2 of the PCB defines the phy as an SMSC LAN8720. I found the data sheet, and yes, indeed, it seems like the registers being accessed do not even exist on the new phy. That would explain why, on the scope, the signal just rises, with no data bits.
So, does anyone already have code? I will proceed, but it would be a help.