Bypass Back Level Protection Use Case

The following table lists the user case for Bypass Back Level Protection.

Table 1. Bypass Back Level Protection Use Case
Step SPI Bitstream Action Result Design Version Design Back Level Version Device Back Level Version
1 Golden/Recovery Auto Programming Pass 2 1 1
2 IAP/Update Bitstream Auto Update/IAP Pass 3 2 2
3 IAP/Update Bitstream Auto Update/IAP Fail, Attempt Programming Recovery 4 Not



The steps are described as follows:

  1. 1.The device programs with a bitstream version 2 and back level version 1. The current device back level version is set to 1.
  2. 2.The device then updates with a bitstream version 3 and back level version 2.
 The current device back level version is set to 2.
  3. 3.The device attempts to update itself with a bitstream version 4 and fails to update. In this case, the device attempts to recover using a golden/recovery bitstream version 2. But the recovery also fails as the current device back level protection is set to version 2 and the golden/recovery bitstream version is equal to the back level version. The Bypass Back Level Protection must be enabled (see Figure 1) for Golden/Recovery bitstream to avoid programming recovery failures because of back level protection.