I updated the firmware to CIS 2.1.3 and had the idea of using the browser to get to wikipedia. As a result, all hell broke loose: I got very dim characters on the screen.
Tried to get back to 2.1.2. No matter whether I try the US, German or CIS 2.1.2 firmware, the 'About' selection reports 2.1.2 (not CIS 2.1.2 as it used to) and the problem of very dim characters is persistent on my pdfs. I tried 2.1.3 and I get the same result. I will give it a try 1-2 more days and then ship it back for a refund. The frustration and time wasted are not worth it...