Boot Search Limit - Boot Search Limit - AM011

Versal Adaptive SoC Technical Reference Manual (AM011)
Document ID
AM011
Release Date
2026-03-06
Revision
1.9 English

The BootROM has a search limit to locate the device image boot header for every boot mode. If a boot mode search limit is reached without a successful boot, the RCU goes into lockdown and the ERROR_OUT pin is set. The following table lists the boot image search limits for each mode.

Table 1. Boot Search Limit
Boot Mode 1 Search Limit 2
OSPI (single, dual-stacked) 8 Gb (1 GB)
QSPI24 (dual-parallel) 256 Mb (32 MB)
QSPI24 (single, dual-stacked) 128 Mb (16 MB)
QSPI32 (dual-parallel) 8 Gb (1 GB)
QSPI32 (single, dual-stacked) 4 Gb (512 MB)
SD and eMMC 8191 FAT files (default)
eMMC (raw) eMMC device size
  1. When using OSPI or QSPI dual-stacked mode, the BootROM can only access the lower QSPI or OSPI addressable flash memory space for boot. After boot, the PLM can access the upper QSPI or OSPI for additional image storage.
  2. The search limit might exceed the size of the flash device. If the size of flash device is less than the search limit, when the RCU BootROM reaches the end of the flash address space, it will wrap around and continue the search at the flash address 0x0 if it has not met the search limit or read a valid image boot header. If the size of flash is equal to or greater than the search limit, the BootROM searches the image up to the search offset limit (example 8 Gb) regardless of which address the search began.
Note: See the Versal Adaptive SoC System Software Developers Guide (UG1304) for PLM fallback/MultiBoot management after a valid boot header is identified by the BootROM.