This is the Iota chip, part of a GSM modem chipset.
For more information: https://osmocom.org/projects/baseband/wiki/TypicalCalypsoModemDesign
Thank you to blackbit for supplying the sample.
2.2. 1 TWL3025 (Logo) (M) TI 2003
The die was covered with PI.
Top metal imaged with LMplan 50x LWD
Top metal imaged with Carl Zeiss PlanApo 40x/1.0