diff --git a/src/modules/partition/core/PartUtils.cpp b/src/modules/partition/core/PartUtils.cpp
index 75a33bf94..4e8b7e8ba 100644
--- a/src/modules/partition/core/PartUtils.cpp
+++ b/src/modules/partition/core/PartUtils.cpp
@@ -536,6 +536,15 @@ parseSizeString( const QString& sizeString, SizeUnit* unit )
     return value;
 }
 
+qint64
+parseSizeString( const QString& sizeString, qint64 totalSize )
+{
+    SizeUnit unit;
+    double value = parseSizeString( sizeString, &unit );
+
+    return sizeToBytes( value, unit, totalSize );
+}
+
 qint64
 sizeToSectors( double size, SizeUnit unit, qint64 totalSectors, qint64 logicalSize )
 {
diff --git a/src/modules/partition/core/PartUtils.h b/src/modules/partition/core/PartUtils.h
index 8b811fd6d..0ad559a60 100644
--- a/src/modules/partition/core/PartUtils.h
+++ b/src/modules/partition/core/PartUtils.h
@@ -107,6 +107,14 @@ QString findFS( QString fsName, FileSystem::Type* fsType );
  */
 double parseSizeString( const QString& sizeString, SizeUnit* unit );
 
+/**
+ * @brief Parse a partition size string and return its value in bytes.
+ * @param sizeString the string to parse.
+ * @param totalSize the size of the selected drive (used when the size is expressed in %)
+ * @return the size value in bytes.
+ */
+qint64 parseSizeString( const QString& sizeString, qint64 totalSize );
+
 /**
  * @brief Convert a partition size to a sectors count.
  * @param size the partition size.
diff --git a/src/modules/partition/core/PartitionActions.cpp b/src/modules/partition/core/PartitionActions.cpp
index 01e794ff6..4172002fa 100644
--- a/src/modules/partition/core/PartitionActions.cpp
+++ b/src/modules/partition/core/PartitionActions.cpp
@@ -29,6 +29,7 @@
 #include "utils/Units.h"
 #include "utils/NamedEnum.h"
 
+#include "GlobalStorage.h"
 #include "JobQueue.h"
 #include "utils/Logger.h"
 
@@ -84,6 +85,7 @@ swapSuggestion( const qint64 availableSpaceB, Choices::SwapChoice swap )
 void
 doAutopartition( PartitionCoreModule* core, Device* dev, Choices::AutoPartitionOptions o )
 {
+    Calamares::GlobalStorage* gs = Calamares::JobQueue::instance()->globalStorage();
     QString defaultFsType = o.defaultFsType;
     if ( FileSystem::typeForName( defaultFsType ) == FileSystem::Unknown )
         defaultFsType = "ext4";
@@ -92,10 +94,18 @@ doAutopartition( PartitionCoreModule* core, Device* dev, Choices::AutoPartitionO
 
     // Partition sizes are expressed in MiB, should be multiples of
     // the logical sector size (usually 512B). EFI starts with 2MiB
-    // empty and a 300MiB EFI boot partition, while BIOS starts at
+    // empty and a EFI boot partition, while BIOS starts at
     // the 1MiB boundary (usually sector 2048).
-    int uefisys_part_sizeB = isEfi ? 300_MiB : 0_MiB;
     int empty_space_sizeB = isEfi ? 2_MiB : 1_MiB;
+    int uefisys_part_sizeB = 0_MiB;
+
+    if ( isEfi )
+    {
+        if ( gs->contains( "efiSystemPartitionSize" ) )
+            uefisys_part_sizeB = PartUtils::parseSizeString( gs->value( "efiSystemPartitionSize" ).toString(), dev->capacity() );
+        else
+            uefisys_part_sizeB = 300_MiB;
+    }
 
     // Since sectors count from 0, if the space is 2048 sectors in size,
     // the first free sector has number 2048 (and there are 2048 sectors
diff --git a/src/modules/partition/gui/PartitionViewStep.cpp b/src/modules/partition/gui/PartitionViewStep.cpp
index 6fc8b0129..ffeb8c055 100644
--- a/src/modules/partition/gui/PartitionViewStep.cpp
+++ b/src/modules/partition/gui/PartitionViewStep.cpp
@@ -3,7 +3,7 @@
  *   Copyright 2014, Aurélien Gâteau <agateau@kde.org>
  *   Copyright 2014-2017, Teo Mrnjavac <teo@kde.org>
  *   Copyright 2018, Adriaan de Groot <groot@kde.org>
- *   Copyright 2019, Collabora Ltd
+ *   Copyright 2019, Collabora Ltd <arnaud.ferraris@collabora.com>
  *
  *   Calamares is free software: you can redistribute it and/or modify
  *   it under the terms of the GNU General Public License as published by
@@ -489,6 +489,12 @@ PartitionViewStep::setConfigurationMap( const QVariantMap& configurationMap )
         efiSP = QStringLiteral( "/boot/efi" );
     gs->insert( "efiSystemPartition", efiSP );
 
+    // Read and parse key efiSystemPartitionSize
+    if ( configurationMap.contains( "efiSystemPartitionSize" ) )
+    {
+        gs->insert( "efiSystemPartitionSize", CalamaresUtils::getString( configurationMap, "efiSystemPartitionSize" ) );
+    }
+
     // SWAP SETTINGS
     //
     // This is a bit convoluted because there's legacy settings to handle as well
diff --git a/src/modules/partition/partition.conf b/src/modules/partition/partition.conf
index f812b67aa..66f40020c 100644
--- a/src/modules/partition/partition.conf
+++ b/src/modules/partition/partition.conf
@@ -3,6 +3,10 @@
 # etc.) use just /boot.
 efiSystemPartition:     "/boot/efi"
 
+# This optional setting specifies the size of the EFI system partition.
+# If nothing is specified, the default size of 300MiB will be used.
+# efiSystemPartitionSize:     300M
+
 # In autogenerated partitioning, allow the user to select a swap size?
 # If there is exactly one choice, no UI is presented, and the user
 # cannot make a choice -- this setting is used. If there is more than