@jockNow, I've finally solved this problem. Successfully flashed the latest version of armbian, https://github.com/armbian/community/releases/download/26.2.0-trunk.151/Armbian_community_26.2.0-trunk.151_Rk3318-box_noble_current_6.12.63_gnome_ desktop.img.xz
Next, I will share my problem-solving journey. I found that I couldn't enter maskrom/loader mode anyway, and when I accidentally inserted the USB flash drive into the multitool.img into the TV box and powered it directly on, I found that it actually started the system directly in the USB flash drive. So I guess that it may have changed the boot order after flashing the loader.bin before, and the armbian system I flashed in before it continued to toss before it could be configured, probably because the system files of the root partition were corrupted, causing it to not boot normally. Therefore, I simply tried to flash the firmware of the rk3188-box in the official community directly into the USB flash drive, because after these images are flashed into the USB flash drive, there is only the root partition, that is, the system. And there is no boot partition. I guess the boot partition may have been written somewhere else, and I don't need to worry about it anymore. So, I plugged the USB flash drive into the latest rk3318 firmware into the box and waited for a few minutes after powering on it directly and starting it, it obtained the IP address assigned by my router DHCP, I was so excited, I quickly connected to the rk3318-box through SSH, and made the preliminary configuration. Quickly enter the command armbian-install and select item 2, and immediately write the system on the USB flash drive to emmc. After the writing is completed, turn it off, unplug the USB flash drive, power on, wait for a few minutes, and the startup is successful. It means that I have successfully flashed the phone this time. Thank you very much for your help. @jockand @fabiobassa, You're passionate and highly skilled.