VxWorks 7 SDK for Raspberry Pi 4 doesn't boot

I’m unable to boot to vxWorks.
I followed the steps in guide: README-raspberrypi4b

I had earlier (January-2023) built using the same steps but somehow I’m unable to do so again.

Boot Log

U-Boot 2023.07-rc3-00015-g26659d4265 (Jun 03 2023 - 20:36:55 +0530)

DRAM: 948 MiB (effective 7.9 GiB)
RPI 4 Model B (0xd03114)
Core: 133 devices, 13 uclasses, devicetree: board
MMC: emmc2@7e340000: 0, mmcnr@7e300000: 1
Loading Environment from FAT… OK
In: serial
Out: serial
Err: serial
Warning: genet@7d580000 MAC addresses don’t match:
Address in DT is e4:5f:01:42:5b:0d
Address in environment is dc:a6:32:07:b3:a4
eth0: genet@7d580000
Hit any key to stop autoboot: 0
12667552 bytes read in 549 ms (22 MiB/s)

Booting kernel from Legacy Image at 00100000 …

Image Name: vxworks
Image Type: AArch64 VxWorks Kernel Image (uncompressed)
Data Size: 12667488 Bytes = 12.1 MiB
Load Address: 00100000
Entry Point: 00100000
Verifying Checksum … OK
Working FDT set to 0
Loading Kernel Image
!!! WARNING !!! Using legacy DTB

Starting vxWorks at 0x00100000, device tree at 0x00000000 …

Your build of U-boot seems to be very recent. If you didn’t update the board firmware since January, going back to a U-Boot checkout from late January would be a good start to troubleshoot the problem. Are you using version 1.4 of the Raspberry Pi 4 SDK?

Yes, I’m using version 1.4 of the Raspberry Pi 4 SDK.

After I rebuilt the entire system using u-boot from January-2023 (v2023.01), I was able to boot vxWorks.

Can you inform me what could have gone wrong?

I have created a read-me file with updated instructions

I am having an issue getting VxWorks to boot on my Raspberry PI 4b. I have downloaded and compiled the latest version of uBoot, version 1.4 of vxWorks and have the lastest Raspberry Pi image. When booting, it simply shows a blank screen. Attached is an image of how far it boots:

Don’t use the latest version of uBoot. Try using u-boot from January-2023 (v2023.01).

The VxWorks kernel image included in the Raspberry Pi 4 SDK v1.4 does not include graphics support, so you’ll need to use a serial adapter as described in the README.

As mentioned by @Ishaan, the latest version of U-Boot may also not work properly, so, while troubleshooting startup issues, try using U-Boot v2023.01.