[U-Boot] u-boot without network boot

[Alexandru Onea]

Hello all,

I am new to u-boot and have played around by compiling for ARM and running
with qemu (as found in may tutorials). However, the default configuration
also includes network boot and I would like to reduce the configuration to
the bare minimum.

I tried removing all networking support and network related boot commands
with

$ make menuconfig

however, I get the following error:

In file included from include/configs/vexpress_common.h:174:0,
                 from include/configs/vexpress_ca9x4.h:14,
                 from include/config.h:5,
                 from include/common.h:20,
                 from env/common.c:10:
include/config_distro_bootcmd.h:333:2: error: expected ‘}’ before
‘BOOT_TARGET_DEVICES_references_PXE_without_CONFIG_CMD_DHCP_or_PXE’
  BOOT_TARGET_DEVICES_references_PXE_without_CONFIG_CMD_DHCP_or_PXE
  ^
include/config_distro_bootcmd.h:333:2: note: in definition of macro
‘BOOTENV_DEV_NAME_PXE’
  BOOT_TARGET_DEVICES_references_PXE_without_CONFIG_CMD_DHCP_or_PXE
  ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
include/configs/vexpress_common.h:172:9: note: in expansion of macro
‘BOOTENV_DEV_NAME’
         func(PXE, pxe, na) \
         ^~~~
include/config_distro_bootcmd.h:339:18: note: in expansion of macro
‘BOOT_TARGET_DEVICES’
  "boot_targets=" BOOT_TARGET_DEVICES(BOOTENV_DEV_NAME) "\0"
                  ^~~~~~~~~~~~~~~~~~~
include/config_distro_bootcmd.h:356:2: note: in expansion of macro
‘BOOTENV_BOOT_TARGETS’
  BOOTENV_BOOT_TARGETS \
  ^~~~~~~~~~~~~~~~~~~~
include/configs/vexpress_common.h:199:17: note: in expansion of macro
‘BOOTENV’
                 BOOTENV \
                 ^~~~~~~
include/env_default.h:111:2: note: in expansion of macro
‘CONFIG_EXTRA_ENV_SETTINGS’
  CONFIG_EXTRA_ENV_SETTINGS
  ^~~~~~~~~~~~~~~~~~~~~~~~~

Of course, the error indicates that the network boot is somehow available
but not the required boot commands. However, I do not understand how to
disable the network boot completely and how to use the BOOT_TARGET_DEVICES
variable.

Please let me know what references I should read to learn more about this
topic.

Thanks and best regards,
Alexandru N. Onea