Hello,
I installed openwrt on a TP Link WDR3600, and it always has the message "Read-only file system"
no matter if I want to download or update the opgk packages or edit some files.
ssh into it:
Your JFFS2-partition seems full and overlayfs is mounted read-only.
Please try to remove files from /overlay/upper/... and reboot!
what can I delete to not lose luci or anything important
Thanks for your help
Run firstboot from ssh, or flash it again.
Deleting packages that came with the image won't actually give you any additional free space.
For that you need to create your own image, containing less packages.
8 MB flash isn't a whole lot, but you still have ~1.0-1.1 MB free space after installing OpenWrt (taking 22.03.0-rc1 as example, older ones should be slightly smaller). firstboot or sysupgrade -n /tmp/…wdr3600…squashfs-sysupgrade.bin should get you going again, but keep in mind the size constraints when installing additional packages.