Since custom firmware isn't an option for this specific model, here is how you can manage some common needs:
You do not need custom firmware to upgrade the storage capacity of your HDR-1100S. If your drive is failing or full, you can physically replace it: The box supports standard 2.5-inch SATA hard drives. humax hdr1100s custom firmware
Plug the USB drive into the front or rear USB port. Since custom firmware isn't an option for this
If you are familiar with older Freesat boxes like the Humax HDR-FOXT2, you probably remember the legendary custom firmware packages created by the independent developer community. Those modifications turned basic recorders into full-fledged network media servers. The Security Hardening Problem If you are familiar with older Freesat boxes
However, enthusiasts have developed side-loading techniques, network exploits, and hardware workarounds to achieve the exact same goals as traditional custom firmware. DLNA Indexing and Decryption Exploits
Humax has moved on to Android TV-based platforms (the AURA 4K). Developer interest in the HDR-1100S is nearly zero. The last significant forum post about custom firmware for this model was in 2020.