eFUSE Readback Protections

Zynq UltraScale+ Device Technical Reference Manual (UG1085)

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2.4 English

In previous generations of AMD devices, the key stored in the eFUSEs could be read out for validation. There were options to close the readback path by blowing additional eFUSEs. This readback path has been removed. The Zynq UltraScale+ MPSoC does not allow read back. Instead, when the key is written, a CRC32 value of that key is provided. After the key has been written, the device verifies that the key in storage matches the provided CRC32. The device then provides a pass or fail result. The read disable eFUSE now prevents the CRC32 validation from occurring.