This is how I create an SD card from the RPi4 SDK.
cp ~/projects/rpi/src/u-boot_2023.01/u-boot.bin /run/media/dan/F0AB-1D53/u-boot-64.bin
cp -r ~/Downloads/firmware-1.20200212/boot/* /run/media/dan/F0AB-1D53/
cp -rLu ~/Downloads/wrsdk-vxworks7-raspberrypi4b-1.4/vxsdk/sdcard/* /run/media/dan/F0AB-1D53/
cp ~/Downloads/wrsdk-vxworks7-raspberrypi4b-1.4/vxsdk/bsps/rpi_4_0_1_3_0/uVxWorks /run/media/dan/F0AB-1D53/
The SD card is usable with my Raspberry Pi 4 board with 4GB of RAM.
The python interpreter can be started as follows:
-> rtpSpStackSize=0x1000000
rtpSpStackSize = 0xffffffff80c33230: value = 16777216 = 0x1000000
-> devs
drv refs name
13 [ 5] /dev/random
13 [ 5] /dev/urandom
12 [ 5] /dev/zero
11 [ 5] /fifos
16 [ 5] /host.host
14 [ 5] /input/event
0 [ 5] /null
10 [ 5] /ram0
5 [ 5] /sd0a
3 [ 5] /shm
10 [ 5] /tmp
2 [ 7] /ttyS0
value = 2 = 0x2
-> cd "/sd0a/"
value = 0 = 0x0
-> cmd python3
Launching process 'python3' ...
Process 'python3' (process Id = 0xffff8000004b41b0) launched.
Python 3.9.5 (default, Mar 15 2022, 17:57:20)
[Clang 12.0.1.2 (http://bitbucket.wrs.com/scm/llvm/clang.git 6953a165f54ad1a885 on vxworks
Type "help", "copyright", "credits" or "license" for more information.
>>> >>> import os;os.name
'posix'
>>> import sys;sys.platform
'vxworks'
>>> >>> >>> ^D
->
The SD card should be formatted as FAT32. If you follow the instructions in the SDK README file you should have a bootable SD card with the Python libraries included. Depending on your hardware revision, you may need to use a newer version of the RPi4 firmware from https://github.com/raspberrypi/firmware/.
Dan