diff --git a/builder/main.py b/builder/main.py
index e11e9587d..9b0b7867e 100644
--- a/builder/main.py
+++ b/builder/main.py
@@ -128,6 +128,7 @@ def __fetch_spiffs_size(target, source, env):
 env.Replace(
     __get_board_f_flash=_get_board_f_flash,
     __get_board_flash_mode=_get_board_flash_mode,
+
     AR="xtensa-esp32-elf-ar",
     AS="xtensa-esp32-elf-as",
     CC="xtensa-esp32-elf-gcc",
@@ -137,6 +138,7 @@ def __fetch_spiffs_size(target, source, env):
         platform.get_package_dir("tool-esptoolpy") or "", "esptool.py"),
     RANLIB="xtensa-esp32-elf-ranlib",
     SIZETOOL="xtensa-esp32-elf-size",
+
     ARFLAGS=["rc"],
     ASFLAGS=["-x", "assembler-with-cpp"],
     CFLAGS=["-std=gnu99"],
@@ -155,9 +157,15 @@ def __fetch_spiffs_size(target, source, env):
         "-nostdlib", "-Wl,-static", "-u", "call_user_start_cpu0",
         "-Wl,--undefined=uxTopUsedPriority", "-Wl,--gc-sections"
     ],
+
+    SIZEPROGREGEXP=r"^(?:\.iram0\.text|\.dram0\.text|\.flash\.text|\.dram0\.data|\.flash\.rodata|)\s+(\d+).*",
+    SIZEDATAREGEXP=r"^(?:\.dram0\.data|\.dram0\.bss)\s+(\d+).*",
+    SIZECHECKCMD="$SIZETOOL -A -d $SOURCES",
+    SIZEPRINTCMD="$SIZETOOL -B -d $SOURCES",
+
     MKSPIFFSTOOL="mkspiffs_${PIOPLATFORM}_${PIOFRAMEWORK}",
-    SIZEPRINTCMD='$SIZETOOL -B -d $SOURCES',
-    PROGSUFFIX=".elf")
+    PROGSUFFIX=".elf"
+)
 
 # Allow user to override via pre:script
 if env.get("PROGNAME", "program") == "program":
@@ -210,7 +218,14 @@ def __fetch_spiffs_size(target, source, env):
 target_buildprog = env.Alias("buildprog", target_firm, target_firm)
 
 # update max upload size based on CSV file
-if "upload" in COMMAND_LINE_TARGETS:
+if env.get("PIOMAINPROG"):
+    env.AddPreAction(
+        "checkprogsize",
+        env.VerboseAction(
+            lambda source, target, env: _update_max_upload_size(env),
+            "Retrieving maximum program size $SOURCES"))
+# remove after PIO Core 3.6 release
+elif set(["checkprogsize", "upload"]) & set(COMMAND_LINE_TARGETS):
     _update_max_upload_size(env)
 
 #
diff --git a/platform.json b/platform.json
index b109632ea..48a133bf3 100644
--- a/platform.json
+++ b/platform.json
@@ -12,7 +12,7 @@
     "type": "git",
     "url": "https://github.com/platformio/platform-espressif32.git"
   },
-  "version": "1.0.1",
+  "version": "1.0.2",
   "packageRepositories": [
     "https://dl.bintray.com/platformio/dl-packages/manifest.json",
     "http://dl.platformio.org/packages/manifest.json",