Wake from RAM fails on the T400. The device reboots to the Libreboot menu with the sleep (moon) light remaining active. The caps and num lock lights flash briefly just before rebooting.
This is an OS-independent issue as it was reproducible on:
The problem remained regardless of whether the disk was encrypted (as one might expect). Hibernation works fine, however.
Forgot to mention I flashed the r20160907 release.
RAM is 4GB, single-rank. Definitely not what is recommended, but everything works fine apart from sleep.
Ordered RAM from Crucial (8GB total) as what is recommended by the guide. I will try again with the new RAM sticks. However, I'm not expecting it to work since I've seen a lot of posts online who have the same problem and tried different RAM.