Update: Shortly after the update botch was noticed by Notion Ink, they halted distribution of the update in question because it was not downloading completely. If you have a bricked Adam, here is the fix as e-mailed to Notion Ink Fan:
How to flash your Adam and get it working again
This fix is recommended only if your Adam has stopped booting up after installing the over-the air system update on 24 January. Please don't use the method indicated to flash your Adam with any ROM not from Notion Ink, as it would probably damage your Adam irreparably.