relation of USB 2.0 problem to excessive device power draw

[dcouzin]

Two years ago there were many discussions here about T40s, T41s and T42s losing their USB 2.0 facilities. Their USB controller reverted to USB 1.1 and displayed a warning to that effect. My T42 had two motherboard replacements and since the second one, thankfully, has provided USB 2.0 for 22 months. (I keep a USB 2.0 cardbus just in case, but since it is not recognized, e.g., by BART PE, it has limited usefulness.)
Based on different theories of the breakdown, there were two maintenance suggestions floated on the forum:
1. avoid flexing the chassis;
2. avoid powering high load devices.
I've followed both suggestions religiously. Concerning flexing, I noticed that one-hand lifting is not a problem itself when high acceleration is avoided. Concerning powering, I acquired a wee 5V 1A power supply and also USB Y-cables.
Unfortunately few small external hard drives today have external power inputs. Also the T42 has just the two USB sockets used by the Y-cable. So the second maintenance suggestion has become a drag, and it would be nice to ignore it, if possible. Has there been any new information on the T4x series USB 2.0 problem showing that powering high load devices is not the cause?
Thanks.