systemd: Failed to disable unit: Read-only file system

I have an embedded system with an operating system built by yocto (Automotive Grade Linux: Halibut 8.0) that has 2 competing dhcp clients: connman and systemd-networkd. sa8155:~# systemctl --type=service connman.service loaded active running Connection service systemd-networkd.service loaded active running Network Service I want to disable connman, but I get this strange error when I try: sa8155:~# systemctl disable connman.service Failed to disable unit: File /etc/systemd/system/multi-user.target.wants/connman.service: Read-only file system I am root. So I'm not sure why it will not allow me to delete this file. sa8155:~# ls -l /etc/systemd/system/multi-user.target.wants/connman.service lrwxrwxrwx 1 root root 35 Nov 27 2019 /etc/systemd/system/multi-user.target.wants/connman.service -> /lib/systemd/system/connman.service sa8155:~# Does anyone know why? What would be the correct way to disable this service? There seems to be an unusual number of file systems: sa8155:~# df -hT Filesystem Type Size Used Avail Use% Mounted on /dev/root ext4 1.4G 504M 812M 39% / devtmpfs devtmpfs 291M 0 291M 0% /dev tmpfs tmpfs 443M 0 443M 0% /dev/shm tmpfs tmpfs 443M 18M 425M 4% /run tmpfs tmpfs 443M 0 443M 0% /sys/fs/cgroup tmpfs tmpfs 443M 18M 425M 4% /etc/machine-id /dev/sde4 vfat 180M 53M 128M 30% /firmware /dev/sde5 vfat 64M 512K 64M 1% /bluetooth /dev/sde9 ext4 59M 21M 38M 36% /dsp /dev/sda2 ext4 122M 12M 108M 10% /var /dev/sda2 ext4 122M 12M 108M 10% /etc/bluetooth /dev/sda2 ext4 122M 12M 108M 10% /persist /dev/sda2 ext4 122M 12M 108M 10% /etc/build.prop /dev/sda2 ext4 122M 12M 108M 10% /etc/usb /dev/sda2 ext4 122M 12M 108M 10% /etc/misc/wifi /dev/sda2 ext4 122M 12M 108M 10% /etc/smack/accesses.d /dev/sda2 ext4 122M 12M 108M 10% /etc/adb_devid tmpfs tmpfs 443M 416K 442M 1% /var/volatile tmpfs tmpfs 443M 416K 442M 1% /persist/volatile /dev/sda8 ext4 108G 6.4G 101G 6% /data /dev/sda8 ext4 108G 6.4G 101G 6% /home tmpfs tmpfs 755M 4.0K 755M 1% /run/user/0 /dev/sda8 ext4 108G 6.4G 101G 6% /home/root/adas/dev /dev/sda8 ext4 108G 6.4G 101G 6% /data/root/adas/dev sa8155:~#