I was thinking about bringing my Foscam FI8910W back into service (assuming it still works), but I've just come across this rather extensive vulnerability disclosure list. I was wondering if there was any trustworthy replacement firmware - maybe openipcam but then I wonder if people have being working on replacement firmware why these zero-days haven't been identified earlier.
Generously, I'd be dubious about hoping the replacement firmware was any improvement over the stock firmware.
You should go with updated firmware, yes. In most cases this is a good idea when you have known vulnerabilities and old firmware (remember there will be more vulnerabilities you don't know about!).
Even if they weren't working on those specific vulnerability fixes, different firmware may have removed some of them anyway, and discovery of new vulnerabilities takes time.
As to your point about identifying zero days - it's generally not something the openipcam folks would have looked at specifically. There will always be vulnerabilities, and many are hard to find. Once found they can be fixed, but up to that point coders will focus on the improvements they are paid to make, hence the popularity of bug bounty programmes.
