ESP-01 boots with GPIOs HIGH
io 0 and io 2 are boot configuration pins. io 2 must not be LOW at startup for correct boot of the esp8266. io 0 determines if the bootloader starts flashing mode. HIGH is for normal boot, LOW for flashing. you must respect this boot requirements of the esp8266.

io 3 is UART TX and it is initialized at startup because it outputs boot log. as UART TX it is HIGH.