Post #1795522

@trini there is a script (https://github.com/AsahiLinux/m1n1/blob/main/proxyclient/tools/linux.py) for m1n1's proxy mode which uploads kernel, initramfs and optionally u-boot and boots them. When using u-boot the script modifies the embedded default environment to boot kernel and initramfs from the known memory addresses. See the script source starting at line 84. This worked with the distro boot scripts since it replaced the complex boot script as that is not necessary. This broke with bootstd as the default environment is tiny and there is not much which can be dropped. I probably got overboard with the 8K padding but one intended use case is https://gitlab.freedesktop.org/gfx-ci/boot2container and I wasn't sure how long the boot arguments for that can get. I started looking how to solve this for upstream u-boot. One option I thought of is using `... char default_environment[CONFIG_ENV_DEFAULT_ENV_EMBEDDED_SIZE] = {` with CONFIG_ENV_DEFAULT_ENV_EMBEDDED_SIZE unset by default. The other one is to let the build system append a configurable sized padding at the end.