diff --git a/src/build_test_firmware.md b/src/build_test_firmware.md
index 7175c8b..2b3606e 100644
--- a/src/build_test_firmware.md
+++ b/src/build_test_firmware.md
@@ -41,7 +41,7 @@ mkdir <variant>
 cd <variant>/
 nix develop github:m-labs/artiq\?ref=release-8#boards
 # master/standalone only
-artiq_mkfs -s ip 192.168.1.75 kasli.config
+artiq_mkfs -s ip 192.168.1.75/24 kasli.config
 artiq_flash storage -f kasli.config
 artiq_ddb_template -o device_db.py <variant>.json 
 python -m artiq.gateware.targets.kasli <variant>.json 
@@ -57,7 +57,7 @@ artiq_coremgmt config write -f device_map dev_map.bin
 1. Build firmware (see commands below) for SD card variant
 2. Copy `results/boot.bin` to the SD card
 3. Insert SD card to the Kasli-SoC and boot
-4. Change IP from the default one: `artiq_coremgmt -D 192.168.1.56 config write -s ip 192.168.1.75`
+4. Change IP from the default one: `artiq_coremgmt -D 192.168.1.56 config write -s ip 192.168.1.75/24`
 5. Reboot and check it works on new IP address
 6. Test hardware with the PSU, which is going to be shipped
 7. Create a flash-drive with `device_db.py` file for customers (FAT32)
@@ -72,7 +72,7 @@ artiq_ddb_template -o device_db.py <variant>.json
 nix build -L --impure --expr 'let fl = builtins.getFlake "git+https://git.m-labs.hk/m-labs/artiq-zynq?ref=release-8"; in (fl.makeArtiqZynqPackage {target="kasli_soc"; variant="[master, standalone, satellite]"; json=<full path to the json description>;}).kasli_soc-[master, standalone, satellite]-sd' 
 # copy `results/boot.bin` to the SD card
 # insert SD card to the Kasli-SoC and boot
-artiq_coremgmt -D 192.168.1.56 config write -s ip 192.168.1.75 # or just place extra/CONFIG.TXT near the boot.bin on SD card
+artiq_coremgmt -D 192.168.1.56 config write -s ip 192.168.1.75/24 # or just place extra/CONFIG.TXT near the boot.bin on SD card
 # update firmware (alternative to copy to SD, if ARTIQ already running)
 artiq_coremgmt config write -f boot result/boot.bin
 artiq_coremgmt reboot
diff --git a/src/extra/CONFIG.TXT b/src/extra/CONFIG.TXT
index 7aca184..17a83e1 100644
--- a/src/extra/CONFIG.TXT
+++ b/src/extra/CONFIG.TXT
@@ -1,2 +1,2 @@
-ip=192.168.1.75
+ip=192.168.1.75/24
 rtio_clock=int_125