What's the technical reason behind the 2010 bank card problems in Germany?

Question

It's been in the news (1) (2), but there's been no technical explanation, besides that it is a software bug on the chip.

Is there any further information on what kind of bug this is? A one-off bug, some number conversion problem or ...?

EDIT: Apparently the bug can be circumvented by modifing the terminals' software. I'd be nice to know, how this is done.

Answer 1

A similar problem what happened with SMS's received by some windows mobile phones. They appeared to come from 2016. This probably had to do with the interpretation of BCD numbers as hexadecimal.

This results in interpreting BCD 10 as decimal 16 instead of decimal 10

maybe something similar happened here.

Answer 2

My guess is that we're simply seeing the results of management cutting costs on development and testing. There is probably just a simple little bug at the bottom of everything, and it escaped QA.