Musebook EC "protocol"

root@k1:~# strace -t -f -e write,read,openat,close /usr/local/bin/k1x_ec
21:46:23 openat(AT_FDCWD, "/etc/ld.so.cache", O_RDONLY|O_CLOEXEC) = 3
21:46:23 close(3)                       = 0
21:46:23 openat(AT_FDCWD, "/lib/riscv64-linux-gnu/libdbus-1.so.3", O_RDONLY|O_CLOEXEC) = 3
21:46:23 read(3, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0\363\0\1\0\0\0\0\0\0\0\0\0\0\0"..., 832) = 832
21:46:23 close(3)                       = 0
21:46:23 openat(AT_FDCWD, "/lib/riscv64-linux-gnu/libc.so.6", O_RDONLY|O_CLOEXEC) = 3
21:46:23 read(3, "\177ELF\2\1\1\3\0\0\0\0\0\0\0\0\3\0\363\0\1\0\0\0\334h\2\0\0\0\0\0"..., 832) = 832
21:46:23 close(3)                       = 0
21:46:23 openat(AT_FDCWD, "/lib/riscv64-linux-gnu/libsystemd.so.0", O_RDONLY|O_CLOEXEC) = 3
21:46:23 read(3, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0\363\0\1\0\0\0\0\0\0\0\0\0\0\0"..., 832) = 832
21:46:23 close(3)                       = 0
21:46:23 openat(AT_FDCWD, "/lib/riscv64-linux-gnu/libcap.so.2", O_RDONLY|O_CLOEXEC) = 3
21:46:23 read(3, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0\363\0\1\0\0\0.k\0\0\0\0\0\0"..., 832) = 832
21:46:23 close(3)                       = 0
21:46:23 openat(AT_FDCWD, "/lib/riscv64-linux-gnu/libgcrypt.so.20", O_RDONLY|O_CLOEXEC) = 3
21:46:23 read(3, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0\363\0\1\0\0\0\0\0\0\0\0\0\0\0"..., 832) = 832
21:46:23 close(3)                       = 0
21:46:23 openat(AT_FDCWD, "/lib/riscv64-linux-gnu/liblzma.so.5", O_RDONLY|O_CLOEXEC) = 3
21:46:23 read(3, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0\363\0\1\0\0\0\0\0\0\0\0\0\0\0"..., 832) = 832
21:46:23 close(3)                       = 0
21:46:23 openat(AT_FDCWD, "/lib/riscv64-linux-gnu/libzstd.so.1", O_RDONLY|O_CLOEXEC) = 3
21:46:23 read(3, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0\363\0\1\0\0\0\0\0\0\0\0\0\0\0"..., 832) = 832
21:46:23 close(3)                       = 0
21:46:23 openat(AT_FDCWD, "/lib/riscv64-linux-gnu/liblz4.so.1", O_RDONLY|O_CLOEXEC) = 3
21:46:23 read(3, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0\363\0\1\0\0\0\0\0\0\0\0\0\0\0"..., 832) = 832
21:46:23 close(3)                       = 0
21:46:23 openat(AT_FDCWD, "/lib/riscv64-linux-gnu/libgpg-error.so.0", O_RDONLY|O_CLOEXEC) = 3
21:46:23 read(3, "\177ELF\2\1\1\0\0\0\0\0\0\0\0\0\3\0\363\0\1\0\0\0\0\0\0\0\0\0\0\0"..., 832) = 832
21:46:23 close(3)                       = 0
21:46:23 openat(AT_FDCWD, "/dev/uinput", O_RDWR|O_NONBLOCK) = 3
21:46:23 write(3, "K1X UART KEY\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 1116) = 1116
21:46:23 openat(AT_FDCWD, "/dev/ttyS2", O_RDWR|O_NOCTTY|O_NONBLOCK) = 4
21:46:23 read(5, "OK 050d3b1f91b0df25233d461a66c77"..., 2048) = 37
21:46:23 read(5, "AGREE_UNIX_FD\r\n", 2048) = 15
21:46:23 write(2, "dbus[11681]: ", 13dbus[11681]: )  = 13
21:46:23 write(2, "A handler is already registered "..., 47A handler is already registered for /k1/ec/comm) = 47
21:46:23 write(2, "\n", 1
)              = 1
strace: Process 11683 attached
strace: Process 11684 attached
[pid 11683] 21:46:23 +++ exited with 0 +++
strace: Process 11685 attached
[pid 11684] 21:46:23 +++ exited with 0 +++
[pid 11685] 21:46:27 write(4, "led_power breath\n", 17) = 17
[pid 11685] 21:46:27 write(4, "led_charge breath\n", 18) = 18
[pid 11685] 21:46:57 write(4, "led_power breath\n", 17) = 17
[pid 11685] 21:46:57 write(4, "led_charge breath\n", 18) = 18
^Cstrace: Process 11681 detached
strace: Process 11685 detached