I need to test further to be sure, but it appears that boron firmware 1.3.0-rc.1 uses approximately 7KB more RAM than 1.2.1-rc.2. Each firmware release seems to use more RAM, leaving little for applications. Has anyone else seen this? At startup I write a log entry showing free memory before initializing anything in setup(). With 1.2.1-rc.2 it usually showed around 69000 bytes free. Updating to 1.3.0-rc.1 now shows around 62000 bytes free.
Some extra RAM usage is owed to the BLE/NFC features added.