Just one datapoint, but I've never heard of ISTQB and have been in industry (primarily information security) for ~10 years with 4 years of CS undergrad before t

Just one datapoint, but I've never heard of ISTQB and have been in industry (primarily information security) for ~10 years with 4 years of CS undergrad before that. I generally see those things as a waste of time and money to get unless you want to work in a very large and very traditional (finance, insurance, etc) company. Engineering background should give you a good foundation for analytical thought and building testing systems. I'd leverage that as well as you can in interviews. Past that, read up a lot on modern approaches to testing and have a working knowledge of the terminology and approach for a few frameworks for ruby/python/java/c# to cover a fair amount of currently popular development languages. Learn a scripting language really really well, whether python or ruby. Best of luck.