The TREZOR people have posted on Reddit that this article is describing a known issue which was fixed in the last firmware update yesterday.
Sure they might have stopped anything getting copied to SRAM, but the data is still sitting there in flash ready to be read out by almost any method.
Contrast cryptography, where no amount of money or human effort could defeat, say, 256-bit symmetric encryption.
The reason this matters is that if you accept that defeating physical defenses is always a matter of money, then you must next decide the attack cost that's sufficiently high to protect your assets.
Then when you learn that the cost to defeat any hardware wallet, including Trezor, is already very high, you understand that we might as well be debating the merits of 255- vs. 256-bit encryption.
(Note that this is not meant to draw an equivalence between hardware Bitcoin wallets and modern symmetric cryptography. There is a big difference. But not a difference that improves the infeasibility of mounting an attack against your Trezor with 25 BTC in it.)
Whereas if it is in a physically protected chip (like many credit card chips), I would feel rather safe knowing the tech and expertise to extract it costs more than half a million dollars.
Breaking into your house to steal a hardware wallet has a significant cost/risk in many people's minds. If someone is willing to break into your house, they're probably also willing to beat you senseless until you transfer them your bitcoin, because you surely value it less than your own life. That's why I think the cost to defeat hardware is high in general, but not especially relevant if your threat model includes targeted attacks.
> Since Trezor has finally provided the hot-fix for this particular hack we can also fully disclose how it works.
But they claim there are other similar hacks