XBL related question

Products Support DragonBoard 820c
#1

Hi all,
I am trying to run a rescue SD card of the DB820C on a modified board. We do not have UFS in our board, and it seems that the XBL is trying to access a UFS which we don’t have, and the system hangs immediately after that. We don’t have the XBL source code yet. My questions are:

  1. Is there an xbl.elf version that was compiled with debug print outs?
  2. Is there a way to force XBL to bypass all UFS access?

The XBL output until it hangs:

Format: Log Type - Time(microsec) - Message - Optional Info
Log Type: B - Since Boot(Power On Reset), D - Delta, S - Statistic
S - QC_IMAGE_VERSION_STRING=BOOT.XF.1.0-00301
S - IMAGE_VARIANT_STRING=M8996LAB
S - OEM_IMAGE_VERSION_STRING=crm-ubuntu68
S - Boot Interface: Unknown
S - Secure Boot: Off
S - Boot Config @ 0x00076044 = 0x000001c1
S - JTAG ID @ 0x000760f4 = 0x4003e0e1
S - OEM ID @ 0x000760f8 = 0x00000000
S - Serial Number @ 0x00074138 = 0xec384c9a
S - OEM Config Row 0 @ 0x00074188 = 0x0000000000000000
S - OEM Config Row 1 @ 0x00074190 = 0x0000000000000000
S - Feature Config Row 0 @ 0x000741a0 = 0x0050000010000100
S - Feature Config Row 1 @ 0x000741a8 = 0x00fff00001ffffff
S - Core 0 Frequency, 19 MHz
B - 0 - PBL, Start
B - 10413 - bootable_media_detect_entry, Start
B - 2490298 - bootable_media_detect_success, Start
B - 2490301 - elf_loader_entry, Start
B - 33526005 - auth_hash_seg_entry, Start
B - 33526110 - auth_hash_seg_exit, Start
B - 33600808 - elf_segs_hash_verify_entry, Start
B - 33604350 - PBL, End
B - 0 - SBL1, Start
B - 33679930 - boot_flash_init, Start

Many thanks
Dave

#2

hi,

sorry about the delay… XBL is proprietary, and at Linaro, we don’t have access to source code. So we don’t know too much about the internals.

For #1: i don’t think so (at least it’s not public)
For #2: which XBL are you using? in the BSP package for 820, there are 2 xbl files, one can be used when booting from UFS, the other one (xbl.sd.elf) is for booting from SD card.

Also, fyi… Geniatech has a board called DB8 which is very similar to 820c, but doesn’t have UFS (but eMMC). maybe you can check what sort of XBL they use/release for their board.
https://www.geniatech.com/product/developer-board-8/

#3

Hi,
Thank you for your reply.
I am using the XBL that came with the DB820C (tried both, including xbl.sd.elf). I tried also some xbl.elf versions that were built for other SnapDragon 820 based designs and they all have the same or very similar behavior.
I looked at Geniatech’s website and it seems that their board also use UFS for storage.

I will try to get a debug version of the XBL until I will have access to the source code, which may take a while to get.

Best regards
Dave