Going live at noon Pacific (just under 2 hours from now): second stage of the ReworkCTF playthrough
Plan is to do the pre-assembly rework of the BGA site (challenge 13), populate the board, then get as far as I can working my way through the challenges.
Post stream: the board is fully populated and challenges 3 and 13 have been (hopefully correctly) solved, but I won't know for sure until I get firmware written to electrically test the connections.
I've hooked up JTAG and the MCU is alive, still need to write firmware to actually grade the challenges so that will be the next step.
Banged up some quick grader firmware.
Confirmed challenges 3 and 13 (the only two I've attempted to bodge to date) are passing, all others failing as expected including the simulated reflow defect on balls A2 and A3.
The simulated reflow defect is the bit I was most concerned about: I put no solder paste apertures on those balls in hopes of creating an open circuit failure, but I didn't know if I might have a good-enough contact between the ENIG and the SAC305 ball sans flux/paste to still make some level of contact.
I got exactly the result I wanted, it failed open.
@AMS I do have a friend with an X-ray system but I won't be X-raying this particular board since I plan to play through the whole challenge before next time I'm in his area. Maybe a future one.
The design is on my github azonenberg/reworkctf in the v2 subdirectory. Just keep in mind I am still play-testing many of the challenges so there may be other defects and difficulty may be higher/lower than intended.
So far I've confirmed the board powers up with no magic smoke and challenges 3 and 13 are good and play as intended.
Andrew Zonenberg
AMS