Samsung Galaxy S5 and the HTC One M8 had “Powered By Android” logo at the bottom of the boot screen. Google has made it mandatory for all the Android devices as a part of Google Mobile Services agreement, according to a report from Geek.com. All the devices that are part of GMS has Google Play Store, Mail etc. Logo placement also has its own separate set of guidelines from Google.
An image from Android Police shows the guidelines for logo placement and the size of the logo, but it doesn’t mention that the logo is mandated. The report says it is compulsory as per their sources. Android devices based on Android Open Source Project like the Nokia X series that doesn’t have Google Play Services doesn’t have any such requirements.
Some smartphone from LG had “with Google” branding and Chromebooks have “made with Google” branding on the back. Making “Powered By Android” boot screen logo compulsory is acceptable, unless they don’t make OEMs etch it on the hardware.
All the new Android devices are expected to come with the new Android boot screen logo. Current devices are likely to get an update to add the logo. This might be officially announced at the Google I/O in June.