diff --git a/scripts/package_release.sh b/scripts/package_release.sh
index f6149c3..52d8e4e 100755
--- a/scripts/package_release.sh
+++ b/scripts/package_release.sh
@@ -194,8 +194,8 @@ if [ -d "$PAYLOAD/hiperiso/ventoy" ]; then
     cp -a "$PAYLOAD/hiperiso/ventoy" "$ESP_STAGING/"
 fi
 
-_progress 6 "Creating 64MB FAT16 ESP image ($(find "$ESP_STAGING" -type f | wc -l) files, $(du -sh "$ESP_STAGING" | cut -f1))..."
-dd if=/dev/zero of="$ESP_IMG" bs=1M count=64 2>/dev/null
+_progress 6 "Creating 32MB FAT16 ESP image ($(find "$ESP_STAGING" -type f | wc -l) files, $(du -sh "$ESP_STAGING" | cut -f1))..."
+dd if=/dev/zero of="$ESP_IMG" bs=1M count=32 2>/dev/null
 # FAT16 volume label MUST be "VTOYEFI" (modsrc's GRUB hardcodes
 # this check at ventoy_check_official_device). Using "HISOEFI" here
 # would fail with error 10 "Partition name is not VTOYEFI".
diff --git a/src/gui/Core/hiperiso_define.h b/src/gui/Core/hiperiso_define.h
index b1f803c..ac9cca0 100644
--- a/src/gui/Core/hiperiso_define.h
+++ b/src/gui/Core/hiperiso_define.h
@@ -28,8 +28,8 @@
 #define HISOIMG_PART_START_BYTES    (1024 * 1024)
 #define HISOIMG_PART_START_SECTOR   2048
 
-#define HISOEFI_PART_BYTES    (64 * 1024 * 1024)
-#define HISOEFI_PART_SECTORS  131072
+#define HISOEFI_PART_BYTES    (32 * 1024 * 1024)
+#define HISOEFI_PART_SECTORS  65536
 
 #pragma pack(1)
 
diff --git a/src/hisocli/hisocli.h b/src/hisocli/hisocli.h
index 82b6e0c..6d21895 100644
--- a/src/hisocli/hisocli.h
+++ b/src/hisocli/hisocli.h
@@ -24,7 +24,7 @@
 #define HIPERISO_EFI_PART_ATTR   0x8000000000000000ULL
 
 #define SIZE_1MB   (1024 * 1024)
-#define HIPERISO_EFI_PART_SIZE   (64 * SIZE_1MB)
+#define HIPERISO_EFI_PART_SIZE   (32 * SIZE_1MB)
 
 #define check_free(p) if (p) free(p)
 #define check_close(fd) if (fd >= 0) close(fd)
diff --git a/src/installer/tool/hiperiso_lib.sh b/src/installer/tool/hiperiso_lib.sh
index 00ea3b4..0b110b7 100644
--- a/src/installer/tool/hiperiso_lib.sh
+++ b/src/installer/tool/hiperiso_lib.sh
@@ -1,14 +1,9 @@
 #!/bin/sh
 
-# Hiperiso partition 2 size. We use 64MB to give the payload room to
-# grow; scripts/build_grub2_204.sh applies a one-line patch to the
-# upstream Ventoy modsrc so its hard-coded 32MB ESP expectation
-# (ventoy_check_official_device) accepts our 64MB layout.
-HIPERISO_PART_SIZE=67108864
-HIPERISO_PART_SIZE_MB=64
-HIPERISO_PART_SIZE=512
+HIPERISO_PART_SIZE=33554432
+HIPERISO_PART_SIZE_MB=32
 HIPERISO_SECTOR_SIZE=512
-HIPERISO_SECTOR_NUM=131072
+HIPERISO_SECTOR_NUM=65536
 
 hiperiso_false() {
     [ "1" = "2" ]
diff --git a/src/plugson/src/Core/hiperiso_define.h b/src/plugson/src/Core/hiperiso_define.h
index 70384f7..aa77eb7 100644
--- a/src/plugson/src/Core/hiperiso_define.h
+++ b/src/plugson/src/Core/hiperiso_define.h
@@ -44,8 +44,8 @@
 #define HISOIMG_PART_START_BYTES    (1024 * 1024)
 #define HISOIMG_PART_START_SECTOR   2048
 
-#define HISOEFI_PART_BYTES    (64 * 1024 * 1024)
-#define HISOEFI_PART_SECTORS  131072
+#define HISOEFI_PART_BYTES    (32 * 1024 * 1024)
+#define HISOEFI_PART_SECTORS  65536
 
 
 #pragma pack(1)