installation/guides/arm-devices: mention images use growpart now

images also aren't 2GB now (more like 700MB but 1G is close enough)

Author: classabbyamp

src/installation/guides/arm-devices/index.md

@@ -27,10 +27,11 @@ thoroughly.
 
 ### Pre-built images
 
-The pre-built images provided are prepared for 2GB SD cards. After [downloading
-and verifying](../../index.md#downloading-installation-media) an image, it can
-be uncompressed with [unxz(1)](https://man.voidlinux.org/unxz.1) and written to
-the relevant media with [cat(1)](https://man.voidlinux.org/cat.1),
+The pre-built images provided are prepared for 1GB storage devices. After
+[downloading and verifying](../../index.md#downloading-installation-media) an
+image, it can be uncompressed with [unxz(1)](https://man.voidlinux.org/unxz.1)
+and written to the relevant media with
+[cat(1)](https://man.voidlinux.org/cat.1),
 [pv(1)](https://man.voidlinux.org/pv.1), or
 [dd(1)](https://man.voidlinux.org/dd.1). For example, to flash it onto an SD
 card located at `/dev/mmcblk0`:
@@ -40,8 +41,13 @@ $ unxz -k <image>.img.xz
 # dd if=<image>.img of=/dev/mmcblk0 bs=4M status=progress
 ```
 
-After flashing, the root partition can optionally be expanded to fit the storage
-device with [cfdisk(8)](https://man.voidlinux.org/cfdisk.8),
+On first boot, the root partition and filesystem will automatically expand to
+fill available space in the storage device using
+[growpart(1)](https://man.voidlinux.org/man1/growpart.1). This can be disabled
+by commenting out `ENABLE_ROOT_GROWPART=yes` in `/etc/default/growpart`.
+
+This can also be done manually after flashing with
+[cfdisk(8)](https://man.voidlinux.org/cfdisk.8),
 [fdisk(8)](https://man.voidlinux.org/fdisk.8), or another partitioning tool, and
 the filesystem can be resized to fit the expanded partition with
 [resize2fs(8)](https://man.voidlinux.org/resize2fs.8).