to elaborate on the second one, it seemingly has a bad solder joint somewhere (it's not U28) and every time it doesn't boot i open up the bottom cover to look at the board. then i try to boot it, and it boots just fine. close it up, use it, next morning it won't boot
i've found that there's a specific way i can flex the board to assure it boots but i can't for the life of me find where the bad connection is. i've reflowed everything i could think of and it'll still refuse to boot on occasion. at least it _does_ boot eventually