Index: Slim/Player/Squeezebox.pm
===================================================================
--- Slim/Player/Squeezebox.pm	(revision 27530)
+++ Slim/Player/Squeezebox.pm	(working copy)
@@ -338,11 +338,9 @@
 
 		main::INFOLOG && $log->info("$model v. $from could be upgraded to v. $to if the file existed.");
 		
-		# We now download firmware from the internet.  In the case of no internet connection
-		# we want to check if the file has appeared later.  This timer will check every 10 minutes
-		Slim::Utils::Timers::killOneTimer( $client, \&checkFirmwareUpgrade );
-		Slim::Utils::Timers::setTimer( $client, time() + 600, \&checkFirmwareUpgrade );
-		
+		# Try to start a background download
+		Slim::Utils::Firmware::downloadAsync($file2, {cb => \&checkFirmwareUpgrade, pt => [$client]});
+				
 		# display an error message
 		$client->showBriefly( {
 			'line' => [ $client->string( 'FIRMWARE_MISSING' ), $client->string( 'FIRMWARE_MISSING_DESC' ) ]
@@ -360,9 +358,8 @@
 
 =head2 checkFirmwareUpgrade($client)
 
-This timer is run every 10 minutes if a client is out of date and a firmware file is not
-present in the Firmware directory.  Another timer in Slim::Utils::Firmware may have
-downloaded firmware in the background, so if the file has appeared, we will prompt
+This callback is run when Slim::Utils::Firmware has
+downloaded firmware in the background, so we will prompt
 the user to upgrade their firmware by holding BRIGHTNESS
 
 =cut
Index: Slim/Utils/Firmware.pm
===================================================================
--- Slim/Utils/Firmware.pm	(revision 27530)
+++ Slim/Utils/Firmware.pm	(working copy)
@@ -205,7 +205,7 @@
 			undef,
 			time(),
 			sub {
-				downloadAsync( $version_file, \&init_version_done, $version_file, $model );
+				downloadAsync( $version_file, {cb => \&init_version_done, pt => [$version_file, $model]} );
 			},
 		);
 	}
@@ -235,7 +235,7 @@
 	if ( !-e $fw_file ) {		
 		main::INFOLOG && $log->info("Downloading $model firmware to: $fw_file");
 	
-		downloadAsync( $fw_file, \&init_fw_done, $fw_file, $model );
+		downloadAsync( $fw_file, {cb => \&init_fw_done, pt => [$fw_file, $model]} );
 	}
 	else {
 		main::INFOLOG && $log->info("$model firmware is up to date: $fw_file");
@@ -465,9 +465,26 @@
 
 =cut
 
+# Keep track of what files are being downloaded and their callbacks
+my %filesDownloading;
+
 sub downloadAsync {
-	my $file = shift;
-	my ( $cb, @pt ) = @_;
+	my ($file, $args) = @_;
+	$args ||= {};
+		
+	# Are we already downloading?
+	my $callbacks;
+	if (!$args->{'retry'} && ($callbacks = $filesDownloading{$file})) {
+		# If we we have more than one caller expecting a callback then stash them here
+		if ($args->{'cb'}) {
+			# XXX maybe check that we do not already have this tuple
+			push @$callbacks, $args;
+		}
+		return;
+	}
+	
+	# Use an empty array ref as the default true value
+	$filesDownloading{$file} ||= [];
 	
 	# URL to download
 	my $url = BASE() . '/' . $::VERSION . '/' . basename($file);
@@ -477,10 +494,9 @@
 		\&downloadAsyncDone,
 		\&downloadAsyncError,
 		{
+			%$args,
 			saveAs => "$file.tmp",
 			file   => $file,
-			cb     => $cb,
-			pt     => \@pt,
 		},
 	);
 	
@@ -497,9 +513,8 @@
 
 sub downloadAsyncDone {
 	my $http = shift;
-	my $file = $http->params('file');
-	my $cb   = $http->params('cb');
-	my $pt   = $http->params('pt');
+	my $args = $http->params();
+	my $file = $args->{'file'};
 	my $url  = $http->url;
 	
 	# make sure we got the file
@@ -511,11 +526,7 @@
 	$http = Slim::Networking::SimpleAsyncHTTP->new(
 		\&downloadAsyncSHADone,
 		\&downloadAsyncError,
-		{
-			file => $file,
-			cb   => $cb,
-			pt   => $pt,
-		},
+		$args,
 	);
 	
 	$http->get( $url . '.sha' );
@@ -529,9 +540,8 @@
 
 sub downloadAsyncSHADone {
 	my $http = shift;
-	my $file = $http->params('file');
-	my $cb   = $http->params('cb');
-	my $pt   = $http->params('pt') || [];
+	my $args = $http->params();
+	my $file = $args->{'file'};
 	
 	# get checksum
 	my ($sum) = $http->content =~ m/([a-f0-9]{40})/;
@@ -554,9 +564,20 @@
 		# reset back off time
 		$CHECK_TIME = INITIAL_RETRY_TIME;
 		
+		my $cb = $args->{'cb'};
 		if ( $cb && ref $cb eq 'CODE' ) {
-			$cb->( @{$pt} );
+			$cb->( @{$args->{'pt'} || []} );
+		}
+		
+		# Pick up extra callbacks waiting for this file
+		foreach $args (@$filesDownloading{$file}) {
+			my $cb = $args->{'cb'};
+			if ( $cb && ref $cb eq 'CODE' ) {
+				$cb->( @{$args->{'pt'} || []} );
+			}
 		}
+		
+		delete $filesDownloading{$file};
 	}
 	else {
 		downloadAsyncError( $http, "Validation of firmware $file failed, SHA1 checksum did not match" );
@@ -600,6 +621,7 @@
 				file => $file,
 				cb   => $cb,
 				pt   => $pt,
+				retry=> 1,
 			},
 		 );