v2025.10 env Kconfig rename (fb5235239aad) removed backward compatibility

[Quentin Schulz]

Hi Ozan,

On 11/22/25 2:18 PM, Ozan Durgut wrote:
> [You don't often get email from ozandurgut.2001 at hotmail.com. Learn why 
> this is important at https://aka.ms/LearnAboutSenderIdentification ]
> 
> Dear U-Boot maintainers,
> 
> I hope you're doing well.
> 
> I would like to raise a backward compatibility concern regarding commit
> fb5235239aad ("env: Rename DEFAULT_ENV_FILE to
> ENV_DEFAULT_ENV_TEXT_FILE"), which landed in the v2025.10 release.
> 

I don't think we ever advertised backward compatibility for Kconfig 
symbols/defconfig.

> Previously used Kconfig symbols CONFIG_USE_DEFAULT_ENV_FILE and
> CONFIG_DEFAULT_ENV_FILE have been replaced with
> CONFIG_ENV_USE_DEFAULT_ENV_TEXT_FILE and
> CONFIG_ENV_DEFAULT_ENV_TEXT_FILE. However, the old symbols were removed
> outright, without a compatibility shim or deprecation period.
> 
> This change causes breakage when integrating U-Boot with Buildroot, as
> Buildroot currently lacks a mechanism to handle such changes
> conditionally based on U-Boot's version. As a result, downstream users
> are forced to choose between breaking support for older or newer U-Boot
> versions.
> 

Currently yes, but that's an issue in Buildroot you can fix. This was 
already asked on #u-boot and I already answered "just enable the new 
option as well?" 
(https://libera.catirclogs.org/u-boot/2025-11-20#39059950;). I've sent a 
patch to the Buildroot ML with a tentative patch (though it doesn't seem 
to appear on the ML archive just yet for some reason):

commit 73889fc15e1d631adc24a88e59f839569fe803dc
Author: Quentin Schulz <quentin.schulz at cherry.de>
Date:   Mon Nov 24 13:20:44 2025 +0100

     boot/uboot: fix externally provided env file not used on 2025.10

     fb5235239aad ("env: Rename DEFAULT_ENV_FILE to
     ENV_DEFAULT_ENV_TEXT_FILE") renamed the Kconfig symbols and thus we 
need
     to adapt the U-Boot package in Buildroot to support it.

     Fixes: 128c26f2875d ("boot/uboot: bump to version 2025.10")
     Reported-by: Ozan Durgut <ozandurgut.2001 at hotmail.com>
     Signed-off-by: Quentin Schulz <quentin.schulz at cherry.de>

diff --git a/boot/uboot/uboot.mk b/boot/uboot/uboot.mk
index 7bd0937df2..8dad710bf3 100644
--- a/boot/uboot/uboot.mk
+++ b/boot/uboot/uboot.mk
@@ -409,8 +409,12 @@ UBOOT_KCONFIG_OPTS = $(UBOOT_MAKE_OPTS) 
HOSTCC="$(HOSTCC_NOCCACHE)" HOSTLDFLAGS=
  ifeq ($(BR2_TARGET_UBOOT_DEFAULT_ENV_FILE_ENABLED),y)
  UBOOT_DEFAULT_ENV_FILE = $(call 
qstrip,$(BR2_TARGET_UBOOT_DEFAULT_ENV_FILE))
  define UBOOT_KCONFIG_DEFAULT_ENV_FILE
+	# Pre-2025.10
  	$(call KCONFIG_SET_OPT,CONFIG_USE_DEFAULT_ENV_FILE,y)
  	$(call KCONFIG_SET_OPT,CONFIG_DEFAULT_ENV_FILE,"$(shell readlink -f 
$(UBOOT_DEFAULT_ENV_FILE))")
+	# 2025.10 and later
+	$(call KCONFIG_SET_OPT,CONFIG_ENV_USE_DEFAULT_ENV_TEXT_FILE,y)
+	$(call KCONFIG_SET_OPT,CONFIG_ENV_DEFAULT_ENV_TEXT_FILE,"$(shell 
readlink -f $(UBOOT_DEFAULT_ENV_FILE))")
  endef
  endif
  endif # BR2_TARGET_UBOOT_BUILD_SYSTEM_LEGACY


Cheers,
Quentin