diff --git a/CHANGELOG.md b/CHANGELOG.md
index 86fad6d2..1706dde7 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,6 +1,14 @@
 CHANGELOG
 =========
 
+0.54.3
+------
+- Fixed incompatibility of adaptive height and 'start:reload'
+- Environment variables are now available to `$FZF_DEFAULT_COMMAND`
+  ```sh
+  FZF_DEFAULT_COMMAND='echo $FZF_QUERY' fzf --query foo
+  ```
+
 0.54.2
 ------
 - Fixed incorrect syntax highlighting of truncated multi-line entries
diff --git a/src/constants.go b/src/constants.go
index 29874b29..980e1583 100644
--- a/src/constants.go
+++ b/src/constants.go
@@ -58,7 +58,6 @@ const (
 const (
 	EvtReadNew util.EventType = iota
 	EvtReadFin
-	EvtReadNone
 	EvtSearchNew
 	EvtSearchProgress
 	EvtSearchFin
diff --git a/src/core.go b/src/core.go
index caada27c..2d1443df 100644
--- a/src/core.go
+++ b/src/core.go
@@ -146,8 +146,23 @@ func Run(opts *Options) (int, error) {
 	// Process executor
 	executor := util.NewExecutor(opts.WithShell)
 
+	// Terminal I/O
+	var terminal *Terminal
+	var err error
+	var initialEnv []string
+	initialReload := opts.extractReloadOnStart()
+	if opts.Filter == nil {
+		terminal, err = NewTerminal(opts, eventBox, executor)
+		if err != nil {
+			return ExitError, err
+		}
+		initialEnv = terminal.environ()
+		var temps []string
+		initialReload, temps = terminal.replacePlaceholderInInitialCommand(initialReload)
+		defer removeFiles(temps)
+	}
+
 	// Reader
-	reloadOnStart := opts.reloadOnStart()
 	streamingFilter := opts.Filter != nil && !sort && !opts.Tac && !opts.Sync
 	var reader *Reader
 	if !streamingFilter {
@@ -155,12 +170,7 @@ func Run(opts *Options) (int, error) {
 			return chunkList.Push(data)
 		}, eventBox, executor, opts.ReadZero, opts.Filter == nil)
 
-		if reloadOnStart {
-			// reload or reload-sync action is bound to 'start' event, no need to start the reader
-			eventBox.Set(EvtReadNone, nil)
-		} else {
-			go reader.ReadSource(opts.Input, opts.WalkerRoot, opts.WalkerOpts, opts.WalkerSkip)
-		}
+		go reader.ReadSource(opts.Input, opts.WalkerRoot, opts.WalkerOpts, opts.WalkerSkip, initialReload, initialEnv)
 	}
 
 	// Matcher
@@ -212,7 +222,7 @@ func Run(opts *Options) (int, error) {
 					}
 					return false
 				}, eventBox, executor, opts.ReadZero, false)
-			reader.ReadSource(opts.Input, opts.WalkerRoot, opts.WalkerOpts, opts.WalkerSkip)
+			reader.ReadSource(opts.Input, opts.WalkerRoot, opts.WalkerOpts, opts.WalkerSkip, initialReload, initialEnv)
 		} else {
 			eventBox.Unwatch(EvtReadNew)
 			eventBox.WaitFor(EvtReadFin)
@@ -234,8 +244,7 @@ func Run(opts *Options) (int, error) {
 	}
 
 	// Synchronous search
-	sync := opts.Sync && !reloadOnStart
-	if sync {
+	if opts.Sync {
 		eventBox.Unwatch(EvtReadNew)
 		eventBox.WaitFor(EvtReadFin)
 	}
@@ -244,18 +253,14 @@ func Run(opts *Options) (int, error) {
 	go matcher.Loop()
 	defer matcher.Stop()
 
-	// Terminal I/O
-	terminal, err := NewTerminal(opts, eventBox, executor)
-	if err != nil {
-		return ExitError, err
-	}
+	// Handling adaptive height
 	maxFit := 0 // Maximum number of items that can fit on screen
 	padHeight := 0
 	heightUnknown := opts.Height.auto
 	if heightUnknown {
 		maxFit, padHeight = terminal.MaxFitAndPad()
 	}
-	deferred := opts.Select1 || opts.Exit0 || sync
+	deferred := opts.Select1 || opts.Exit0 || opts.Sync
 	go terminal.Loop()
 	if !deferred && !heightUnknown {
 		// Start right away
@@ -322,9 +327,6 @@ func Run(opts *Options) (int, error) {
 					err = quitSignal.err
 					stop = true
 					return
-				case EvtReadNone:
-					reading = false
-					terminal.UpdateCount(0, false, nil)
 				case EvtReadNew, EvtReadFin:
 					if evt == EvtReadFin && nextCommand != nil {
 						restart(*nextCommand, nextEnviron)
diff --git a/src/options.go b/src/options.go
index d32daf10..1593d6f8 100644
--- a/src/options.go
+++ b/src/options.go
@@ -2964,17 +2964,18 @@ func ParseOptions(useDefaults bool, args []string) (*Options, error) {
 	return opts, nil
 }
 
-func (opts *Options) reloadOnStart() bool {
-	// Not compatible with --filter
-	if opts.Filter != nil {
-		return false
-	}
+func (opts *Options) extractReloadOnStart() string {
+	cmd := ""
 	if actions, prs := opts.Keymap[tui.Start.AsEvent()]; prs {
+		filtered := []*action{}
 		for _, action := range actions {
 			if action.t == actReload || action.t == actReloadSync {
-				return true
+				cmd = action.a
+			} else {
+				filtered = append(filtered, action)
 			}
 		}
+		opts.Keymap[tui.Start.AsEvent()] = filtered
 	}
-	return false
+	return cmd
 }
diff --git a/src/reader.go b/src/reader.go
index a4049c4e..ccaf8c62 100644
--- a/src/reader.go
+++ b/src/reader.go
@@ -111,18 +111,20 @@ func (r *Reader) readChannel(inputChan chan string) bool {
 }
 
 // ReadSource reads data from the default command or from standard input
-func (r *Reader) ReadSource(inputChan chan string, root string, opts walkerOpts, ignores []string) {
+func (r *Reader) ReadSource(inputChan chan string, root string, opts walkerOpts, ignores []string, initCmd string, initEnv []string) {
 	r.startEventPoller()
 	var success bool
 	if inputChan != nil {
 		success = r.readChannel(inputChan)
+	} else if len(initCmd) > 0 {
+		success = r.readFromCommand(initCmd, initEnv)
 	} else if util.IsTty(os.Stdin) {
 		cmd := os.Getenv("FZF_DEFAULT_COMMAND")
 		if len(cmd) == 0 {
 			success = r.readFiles(root, opts, ignores)
 		} else {
 			// We can't export FZF_* environment variables to the default command
-			success = r.readFromCommand(cmd, nil)
+			success = r.readFromCommand(cmd, initEnv)
 		}
 	} else {
 		success = r.readFromStdin()
diff --git a/src/terminal.go b/src/terminal.go
index f43bb8e9..09a08985 100644
--- a/src/terminal.go
+++ b/src/terminal.go
@@ -2946,6 +2946,10 @@ type replacePlaceholderParams struct {
 	executor   *util.Executor
 }
 
+func (t *Terminal) replacePlaceholderInInitialCommand(template string) (string, []string) {
+	return t.replacePlaceholder(template, false, string(t.input), []*Item{nil, nil})
+}
+
 func (t *Terminal) replacePlaceholder(template string, forcePlus bool, input string, list []*Item) (string, []string) {
 	return replacePlaceholder(replacePlaceholderParams{
 		template:   template,