You can wipe htc One cache partition to improve battery life, especially after ROM upgrade.
My One had a lot of wakelocks after KK upgrade from Google Play services.The method below resolves this issue.
- To do this, first ensure Fast Boot is un-checked under Settings > Power.
- Next, power off the phone
- Access the Bootloader menu by holding down the Volume Down button, and pressing Power. Your phone should boot up.
- When you see a white screen with three cartoon Androids, release the buttons.
- You should see a menu (white background)
- Use Volume to highlight "RECOVERY" and tap Power to select.
- Your phone will reboot and display a black screen with a red exclamation mark in a red triangle.
- Press Volume Up and Power. Release once buttons are flashing couple of times.
- You should see another menu. (dark background)
- Highlight and select "Wipe cache partition" (before tapping Power to select, be sure that "Wipe data/factory reset" is NOT highlighted, as this will result in loss of data).
- When the process is complete, highlight and select "Reboot system" to boot the phone into the OS