We used NFC Read Write App to write NDEF data to ISO 15693 SLI on-metal tags and read back to validate.
Before we found the NFC Read Write App, we attempted to write the tags with the following apps, and all failed.
NFC tools (This NFC tag is not supported!)
NFC reader (no read)
NFC Master (NFC Error)
NFC Manager (Tag is not NDEF)