diff --git a/CLAUDE.md b/CLAUDE.md
index d978820..8166469 100644
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -37,8 +37,35 @@ docker compose logs -f wg-easy
 
 ## Important constraints
 
-- `wg-data/` is auto-generated by the container on first start and holds live WireGuard keys (`wg0.conf`, `wg0.json`). Never commit it.
+- `wg-data/` is auto-generated by the container on first start and holds live WireGuard keys (`wg0.conf`, `wg-easy.db`). Never commit it. Permissions are set to `700` automatically by `wg-init`.
 - `.env` is gitignored.
 - The container requires `NET_ADMIN` and `SYS_MODULE` capabilities plus `net.ipv4.ip_forward=1` sysctl — these are already set in `docker-compose.yml`.
 - The router must forward UDP port 51820 (or `WG_PORT`) to the server's local IP.
 - `INSECURE=true` is set in `docker-compose.yml` to allow HTTP access on the local network.
+
+## SBC / resource-constrained devices
+
+Works on any Linux host with a 64-bit kernel and WireGuard support. Tested architectures:
+
+| Hardware | Arch | Notes |
+|---|---|---|
+| Raspberry Pi 5 | arm64 | kernel `6.12.x+rpt-rpi-2712` |
+| Raspberry Pi 4 / 3B+ | arm64 / armv7 | 32-bit kernels need `armv7` image |
+| Orange Pi, Rock Pi, Banana Pi | arm64 | depends on board BSP kernel |
+| Generic x86\_64 server / VM | amd64 | standard Debian/Ubuntu/Fedora |
+| Intel NUC / mini-PC | amd64 | same as above |
+
+**Known issue — ip6tables modules not loaded at boot.**
+Affects mostly SBC boards with custom BSP kernels, but can occur on any host where `ip6_tables` and `ip6table_nat` are not auto-loaded. Without them `wg-quick up wg0` fails and rolls back, leaving no `wg0` interface. Symptom: every API call returns `Command failed: wg show wg0 dump / No such device`.
+
+The `wg-init` service handles this automatically: it runs `modprobe ip6_tables ip6table_nat` (with `SYS_MODULE` cap and `/lib/modules` bind-mounted read-only) before wg-easy starts. Failures are silenced (`|| true`) so the setup works on kernels where these modules are built-in or unavailable.
+
+**Resource limits** (`docker-compose.yml`):
+
+| Variable | Default | Purpose |
+|---|---|---|
+| `WG_MEM_LIMIT` | `256m` | Hard memory cap for wg-easy |
+| `WG_MEMSWAP_LIMIT` | `256m` | Disables swap (swap = mem limit) |
+| `WG_CPUS` | `1.0` | CPU share (1 core) |
+
+Lower `WG_MEM_LIMIT` to `128m` on boards with less than 1 GB RAM. Do not set it below `96m` or the Node.js runtime will OOM-kill on startup.