If you solve the above problems, let’s take a look at the following situation.
Does black still have a chance to win?
Here are ly_go’s puzzles in an interactive form.
I entered my solutions, but maybe @ly_go found a different solution.
ly_go Problem 1
ly_go Problem 2
I’m not sure they are right.
The first problem has two branches, one of them is the second problem.
I think that the second problem solution doesn’t work, because white can make seki.
I don’t see how black could prevent it.
If that’s true, white wouldn’t use the other branch in first problem, so they would be the same.
Well, let’s hope that ly_go comes up with the solutions.
I wasn’t sure about them either.
Edit: concerning the first puzzle: I entered @Glunkolin’s solution.
I missed another important variation. I’m not sure if my solution still works.
If black takes at B7 and white takes at D8, then the situation will be this.
Note that white has no ko threat and black has a threat at E2 which is not big enough. Now if black connects at A7 or E9 then white takes the other ko and lives, but black can play D6. If white takes one ko then black takes the other. In both cases, It’s black to take the ko so white dies.