diff --git a/README.md b/README.md
index 62d2377..620efd8 100644
--- a/README.md
+++ b/README.md
@@ -29,3 +29,10 @@ This creates file `build/bootloader-TAG.bin` and prints its fingerprint and size
 3. Compute fingerprint: `tail -c +257 trezor.signed.bin | sha256sum`
 
 Step 3 should produce the same sha256 fingerprint like your local build (for the same version tag). Firmware has a special header (of length 256 bytes) holding signatures themselves, which must be avoided while calculating the fingerprint, that's why tail command has to be used.
+
+## How to install custom built firmware?
+
+**WARNING: This will erase the recovery seed stored on the device! You should never do this on TREZOR that contains coins!**
+
+1. Install python-trezor: `pip install trezor`, (<a href="https://github.com/trezor/python-trezor">more info</a>
+2. `trezorctl firmware_update -f build/trezor-TAG.bin`