nixos/sdcard: make firmware partition offset configurable

Different boards using u-boot SPL require to write to different
locations. Sometimes, the 8MiB gap isn't sufficient - rk3399 boards
write to 0x16384 for example, which is at 8MiB, thus overriding the
fat32 partition with the SPL.
This commit is contained in:
Florian Klink 2021-06-25 11:35:25 +02:00
parent 3affea2a73
commit 1db54a5522

View file

@ -55,6 +55,22 @@ in
'';
};
firmwarePartitionOffset = mkOption {
type = types.int;
default = 8;
description = ''
Gap in front of the /boot/firmware partition, in mebibytes (1024×1024
bytes).
Can be increased to make more space for boards requiring to dd u-boot
SPL before actual partitions.
Unless you are building your own images pre-configured with an
installed U-Boot, you can instead opt to delete the existing `FIRMWARE`
partition, which is used **only** for the Raspberry Pi family of
hardware.
'';
};
firmwarePartitionID = mkOption {
type = types.str;
default = "0x2178694e";
@ -177,7 +193,7 @@ in
zstd -d --no-progress "${rootfsImage}" -o ./root-fs.img
# Gap in front of the first partition, in MiB
gap=8
gap=${toString config.sdImage.firmwarePartitionOffset}
# Create the image file sized to fit /boot/firmware and /, plus slack for the gap.
rootSizeBlocks=$(du -B 512 --apparent-size ./root-fs.img | awk '{ print $1 }')