sd-image.nix: Move the /boot partition up to 8M

Reportedly some ARM boards need some boot code at the start of a SD card
that could be larger than a megabyte. Change it to 8M, and while at it
reduce the /boot size such that the root partition should now start on a
128M boundary (the flash on SD cards really don't like non-aligned
writes these days).
This commit is contained in:
Tuomas Tynkkynen 2015-12-26 07:28:19 +02:00
parent b6621196e0
commit 4cf9bf9eb0

View File

@ -30,7 +30,7 @@ in
bootSize = mkOption {
type = types.int;
default = 128;
default = 120;
description = ''
Size of the /boot partition, in megabytes.
'';
@ -66,10 +66,10 @@ in
buildInputs = with pkgs; [ dosfstools e2fsprogs mtools libfaketime utillinux ];
buildCommand = ''
# Create the image file sized to fit /boot and /, plus 4M of slack
# Create the image file sized to fit /boot and /, plus 20M of slack
rootSizeBlocks=$(du -B 512 --apparent-size ${rootfsImage} | awk '{ print $1 }')
bootSizeBlocks=$((${toString config.sdImage.bootSize} * 1024 * 1024 / 512))
imageSize=$((rootSizeBlocks * 512 + bootSizeBlocks * 512 + 4096 * 1024))
imageSize=$((rootSizeBlocks * 512 + bootSizeBlocks * 512 + 20 * 1024 * 1024))
truncate -s $imageSize $out
# type=b is 'W95 FAT32', type=83 is 'Linux'.
@ -77,8 +77,8 @@ in
label: dos
label-id: 0x2178694e
start=1M, size=$bootSizeBlocks, type=b, bootable
type=83
start=8M, size=$bootSizeBlocks, type=b, bootable
start=${toString (8 + config.sdImage.bootSize)}M, type=83
EOF
# Copy the rootfs into the SD image