the WLCSP ASIC is labelled EF71XW1, which doesn't have any hits. I know this is some disgusting Renesas device based on firmware analysis. I fucking hate Renesas. I cannot put into words how much I hate Renesas. So of course it is Renesas
it seems to have exposed JTAG, so after I'm done doing what I want with the bike I might plug it into Glasgow and see if I can get at least an IDCODE out of it. of course actual debug is almost certainly impossible