I am trying to flash my old ZyXEL WAP3205 v1. I did exactly what it says in this description: https://openwrt.org/toh/zyxel/nbg419n
Connected to serial interface (using USB to TTL Serial Cable) and can see U-Boot. Description says "When you see U-Boot prompt, press 2:". But U-Boot doesn't prompt me for anything. It selects "3: Boot system code via Flash (default)." without prompting, and boots. I don't know what am I missing.
Description also says " If you miss the bootloader (U-Boot) prompt, wait until ZyXEL Linux boots and issue halt or reboot .". But I don't know how to " issue halt or reboot .". I am using Putty.