diff --git a/doc/cli.markdown b/doc/cli.markdown
index 78fcaa2c..6e3ab7c2 100644
--- a/doc/cli.markdown
+++ b/doc/cli.markdown
@@ -1712,10 +1712,11 @@ how frequently (in minutes) to poll for application updates
 ## preload <image>
 
 Preload a balena application release (app images/containers), and optionally
-a balenaOS splash screen, in a previously downloaded balenaOS image file (or
-Edison zip archive) in the local disk. The balenaOS image file can then be
-flashed to a device's SD card.  When the device boots, it will not need to
-download the application, as it was preloaded.
+a balenaOS splash screen, in a previously downloaded '.img' balenaOS image file
+in the local disk (a zip file is only accepted for the Intel Edison device type).
+After preloading, the balenaOS image file can be flashed to a device's SD card.
+When the device boots, it will not need to download the application, as it was
+preloaded.
 
 Warning: "balena preload" requires Docker to be correctly installed in
 your shell environment. For more information (including Windows support)
diff --git a/lib/actions/preload.js b/lib/actions/preload.js
index a3993a1b..6b1beb52 100644
--- a/lib/actions/preload.js
+++ b/lib/actions/preload.js
@@ -239,10 +239,11 @@ export const preload = {
 	description: 'preload an app on a disk image (or Edison zip archive)',
 	help: `\
 Preload a balena application release (app images/containers), and optionally
-a balenaOS splash screen, in a previously downloaded balenaOS image file (or
-Edison zip archive) in the local disk. The balenaOS image file can then be
-flashed to a device's SD card.  When the device boots, it will not need to
-download the application, as it was preloaded.
+a balenaOS splash screen, in a previously downloaded '.img' balenaOS image file
+in the local disk (a zip file is only accepted for the Intel Edison device type).
+After preloading, the balenaOS image file can be flashed to a device's SD card.
+When the device boots, it will not need to download the application, as it was
+preloaded.
 
 Warning: "balena preload" requires Docker to be correctly installed in
 your shell environment. For more information (including Windows support)