For Raspberry Pi OS Lite 64-bit, the most reliable and modern way to ensure WiFi power management stays disabled after every reboot is to create a systemd service. This method is robust, works with headless setups, and is not dependent on deprecated files like /etc/network/interfaces or /etc/rc.local, which may not be effective on current versions[^1][^2].

Steps to Permanently Disable WiFi Power Management

1. Create a systemd service file:

Open a terminal and run:

sudo nano /etc/systemd/system/wlan0pwr.service

2. Paste the following configuration:

[Unit]
Description=Disable wlan0 powersave
After=network-online.target
Wants=network-online.target

[Service]
Type=oneshot
ExecStart=/sbin/iw wlan0 set power_save off

[Install]
WantedBy=multi-user.target

3. Save and exit (Ctrl+X, then Y, then Enter).

4. Enable the service:

sudo systemctl enable wlan0pwr

5. Reboot your Raspberry Pi:

sudo reboot

6. Verify the setting:

After reboot, check that power management is off:

iwconfig

Look for Power Management:off in the output.