Apple Time Capsule Custom Firmware <4K | 8K>

Instead of replacing the firmware on the Time Capsule itself, keep the stock firmware intact but disable its Wi-Fi routing capabilities (switch it to "Bridge Mode"). You can then connect it via an Ethernet cable to a modern router running OpenWrt, DD-WRT, or FreshTomato.

You will need to make the file system writable. apple time capsule custom firmware