Rename cIOS38rev17_installer.dol to boot.dol and place in a folder (name this folder whatever you like) within the apps folder on your card. Like this:
With IOS38-64-v3867.wad at the root of the SD card, run your cIOS38 folder above directly through HBC, do not use wad manager. If it asks use IOS249 to install and select Wad installation, wait for it to finish and once you've returned past the HBC screen, power down and reboot the console. The cIOS should now be properly installed.