Softbrick by invalid network config: allow hot-plug

[fricy]

Addding the option "allow hot-plug wlan0" in etc/network/interfaces or etc/network/interfaces.d/wlan0 stopped network from initializing, making the camera unreachable on eth0 too. Softbricked camera could only be recovered on serial.

I tried the option, because after a firmware upgrade wlan0 wouldn't start automatically.

Starting network...
ifup: misplaced option "allow"
ifup: misplaced option "allow"
Starting ntpd: OK
Starting dropbear: OK
Starting crond: OK
Loading vendor modules...
mmz_start: 0x82000000, mmz_size: 96M
hisilicon: Manualy set SENSOR as imx291_i2c
==== Your input Sensor type is imx291_i2c ====
Starting majestic: OK

Vendor hisilicon
SoC hi3516cv300
Kernel 11:14:04 2025-09-13
RootFS local+build, 2025-09-13

Ultimate firmware built from sources with RTL8188EUS

problematic etc/network/interfaces :

auto lo
iface lo inet loopback

auto wlan0
allow hot-plug wlan0
iface wlan0 inet dhcp
    # load modules
    pre-up echo 63 > /sys/class/gpio/export
    pre-up echo out > /sys/class/gpio/gpio63/direction
    pre-up echo 0 > /sys/class/gpio/gpio63/value
    pre-up modprobe 8188eu
    # configure access
    pre-up wpa_passphrase "SSID" "passwd" >/tmp/wpa_supplicant.conf
    pre-up sed -i '2i \\tscan_ssid=1' /tmp/wpa_supplicant.conf
    pre-up sleep 3
    pre-up wpa_supplicant -B -D nl80211 -i wlan0 -c/tmp/wpa_supplicant.conf
    # unload modules
    post-down rmmod 8188eu
    postdown sleep 3
    post-down killall -q wpa_supplicant
    post-down echo 1 > /sys/class/gpio/gpio63/value
    post-down echo 63 > /sys/class/gpio/unexport

auto eth0
iface eth0 inet dhcp
    hwaddress ether $(fw_printenv -n ethaddr || echo 00:00:23:34:45:66)
    #udhcpc_opts -O search -O ntpsrv -O hostname
    #pre-up echo -e "nameserver 77.88.8.8\nnameserver 8.8.4.4\n" >/tmp/resolv.conf
    #pre-up echo -e "server 0.time.openipc.org iburst\nserver 1.time.openipc.org iburst\nserver 2.time.openipc.org iburst\nserver 3.time.openipc.org iburst" >/tmp/ntp.conf
    #up /usr/sbin/ntpd -N -q

#source-dir /etc/network/interfaces.d