Today I received 3 more DC/DC converters marked CN2596-2 which are similar to the one described before. Visible differences are the pads for a ICP (in circuit programming) header on the back of the PCB, and that they're green.

Although the PCB was redesigned, but it doesn't look like the more obvious shortcomings (no current limiting resistors for LEDs, keys share port with 7S-LED, no blocking capacitor for VCC) have been improved (but I'll open one to be sure).

In order to make modding one easy, I'll try to modify the boards with a few simple steps.