diff --git a/internal/base/Optional.go b/internal/base/Optional.go
index 4c1460f..6f5b290 100644
--- a/internal/base/Optional.go
+++ b/internal/base/Optional.go
@@ -43,6 +43,12 @@ func (x Optional[T]) GetOrElse(orElse T) T {
 		return orElse
 	}
 }
+func (x *Optional[T]) WhatIf(cond func(*T) error) error {
+	if x.err == nil {
+		return cond(&x.value)
+	}
+	return nil
+}
 
 func SetOptional[T any, E interface {
 	*T
diff --git a/internal/base/SerializableHelpers.go b/internal/base/SerializableHelpers.go
index 540e97e..664b2ed 100644
--- a/internal/base/SerializableHelpers.go
+++ b/internal/base/SerializableHelpers.go
@@ -22,6 +22,12 @@ func (x *Regexp) Set(in string) (err error) {
 	x.Regexp, err = regexp.Compile(in)
 	return
 }
+func (x Regexp) String() string {
+	if x.Regexp != nil {
+		return x.Regexp.String()
+	}
+	return ""
+}
 func (x *Regexp) MarshalText() ([]byte, error) {
 	return UnsafeBytesFromString(x.String()), nil
 }
diff --git a/internal/hal/generic/ExternalSDK.go b/internal/hal/generic/ExternalSDK.go
index b39987a..f910fa2 100644
--- a/internal/hal/generic/ExternalSDK.go
+++ b/internal/hal/generic/ExternalSDK.go
@@ -76,10 +76,12 @@ func (x ExternalSDKHeaderGenerator) CreateGenerated(unit *compile.Unit, output u
 		return nil, err
 	}
 
-	// Archive
+	// Archive from local filesystem
 	if err := setOptionalSdkParam(unit, "SDK/ArchiveFile", &result.ArchiveFile); err != nil {
 		return nil, err
 	}
+
+	// Archive from remote url
 	if err := setOptionalSdkParam(unit, "SDK/ArchiveURL", &result.ArchiveURL); err != nil {
 		return nil, err
 	}
@@ -87,15 +89,6 @@ func (x ExternalSDKHeaderGenerator) CreateGenerated(unit *compile.Unit, output u
 		return nil, err
 	}
 
-	// construct absolute path from relative dirname provided (or not in the configuration)
-	var extractDirname base.Optional[base.InheritableString]
-	if err := setOptionalSdkParam(unit, "SDK/ExtractDirname", &extractDirname); err != nil {
-		return nil, err
-	}
-	if relativeDirname, err := extractDirname.Get(); err == nil {
-		result.ExtractDir = base.NewOption(unit.ModuleDir.AbsoluteFolder(relativeDirname.Get()))
-	}
-
 	// Headers/Libraries
 	if err := setOptionalSdkParam(unit, "SDK/Headers", &result.Headers); err != nil {
 		return nil, err
@@ -110,6 +103,15 @@ func (x ExternalSDKHeaderGenerator) CreateGenerated(unit *compile.Unit, output u
 		return nil, err
 	}
 
+	// Construct absolute path from relative dirname provided (or not in the configuration)
+	var extractDirname base.Optional[base.InheritableString]
+	if err := setOptionalSdkParam(unit, "SDK/ExtractDirname", &extractDirname); err != nil {
+		return nil, err
+	}
+	if relativeDirname, err := extractDirname.Get(); err == nil {
+		result.ExtractDir = base.NewOption(unit.ModuleDir.AbsoluteFolder(relativeDirname.Get()).Normalize())
+	}
+
 	// Relative include sub-directory in external SDK (defaults to "./include/")
 	if err := setOptionalSdkParam(unit, "SDK/IncludeDirname", &result.IncludeDirname); err != nil {
 		return nil, err
@@ -184,7 +186,16 @@ func (x *ExternalSDKGeneratedHeader) prepareSDKDir(bc utils.BuildContext) (utils
 		base.LogVerbose(LogExternalSDK, "%s: using external directory %q for external SDK", x.SDKName, sdkDir)
 
 		// External SDK stored at designated location
-		sdkFiles, err := internal_io.ListDirectory(bc, sdkDir)
+		sdkFiles, err := internal_io.MatchDirectory(bc, sdkDir,
+			base.Regexp{}, base.Regexp{}, utils.FileSet{})
+
+		if err == nil {
+			acceptListRe := x.getArchiveAcceptList()
+			sdkFiles = base.RemoveUnless(func(f utils.Filename) bool {
+				return acceptListRe.MatchString(f.Relative(sdkDir))
+			}, sdkFiles...)
+		}
+
 		return sdkDir, sdkFiles, err
 
 	} else if extractDir, err := x.ExtractDir.Get(); err == nil {
@@ -297,7 +308,7 @@ func (x *ExternalSDKGeneratedHeader) Generate(bc utils.BuildContext, generated *
 		}
 	}
 
-	base.LogVerbose(LogExternalSDK, "%s: found %d SDK library files %q", x.SDKName, len(sdkLibraries))
+	base.LogVerbose(LogExternalSDK, "%s: found %d SDK library files", x.SDKName, len(sdkLibraries))
 	if base.IsLogLevelActive(base.LOG_VERYVERBOSE) {
 		for _, it := range sdkLibraries {
 			base.LogVeryVerbose(LogExternalSDK, "%s: found SDK library %q", x.SDKName, it)
diff --git a/internal/io/IO.go b/internal/io/IO.go
index 4f8221c..e2b9ed9 100644
--- a/internal/io/IO.go
+++ b/internal/io/IO.go
@@ -24,8 +24,9 @@ func InitIO() {
 	base.RegisterSerializable[Downloader]()
 
 	base.RegisterSerializable[DirectoryCreator]()
-	base.RegisterSerializable[DirectoryGlob]()
 	base.RegisterSerializable[DirectoryList]()
+	base.RegisterSerializable[DirectoryMatch]()
+
 	base.RegisterSerializable[FileDigest]()
 }
 
@@ -196,74 +197,77 @@ func GlobDirectory(
 	includedGlobs base.StringSet,
 	excludedGlobs base.StringSet,
 	excludedFiles utils.FileSet) (utils.FileSet, error) {
-	factory := BuildDirectoryGlob(source, includedGlobs, excludedGlobs, excludedFiles)
-	if glob, err := factory.Need(bc); err == nil {
-		return glob.Results, nil
+	return MatchDirectory(bc, source,
+		utils.MakeGlobRegexp(includedGlobs...),
+		utils.MakeGlobRegexp(excludedGlobs...),
+		excludedFiles)
+}
+
+/***************************************
+ * Directory Match
+ ***************************************/
+
+func MatchDirectory(
+	bc utils.BuildContext,
+	source utils.Directory,
+	includedRe base.Regexp,
+	excludedRe base.Regexp,
+	excludedFiles utils.FileSet) (utils.FileSet, error) {
+	factory := BuildDirectoryMatch(source, includedRe, excludedRe, excludedFiles)
+	if match, err := factory.Need(bc); err == nil {
+		return match.Results, nil
 	} else {
 		return utils.FileSet{}, err
 	}
 }
 
-type DirectoryGlob struct {
+type DirectoryMatch struct {
 	Source        utils.Directory
-	IncludedGlobs base.StringSet
-	ExcludedGlobs base.StringSet
+	IncludedRe    base.Regexp
+	ExcludedRe    base.Regexp
 	ExcludedFiles utils.FileSet
-	Results       utils.FileSet
+
+	Results utils.FileSet
 }
 
-func BuildDirectoryGlob(
+func BuildDirectoryMatch(
 	source utils.Directory,
-	includedGlobs base.StringSet,
-	excludedGlobs base.StringSet,
-	excludedFiles utils.FileSet) utils.BuildFactoryTyped[*DirectoryGlob] {
+	includedRe base.Regexp,
+	excludedRe base.Regexp,
+	excludedFiles utils.FileSet) utils.BuildFactoryTyped[*DirectoryMatch] {
 	base.Assert(func() bool { return source.Valid() })
-	base.Assert(func() bool { return len(includedGlobs) > 0 })
 
-	// make build alias determinist for DirectoryGlob
-	includedGlobs.Sort()
-	excludedGlobs.Sort()
+	if !includedRe.Valid() {
+		includedRe = utils.MakeGlobRegexp("*")
+	}
 
+	// make build alias determinist for DirectoryGlob
 	excludedFiles = excludedFiles.Normalize()
 	excludedFiles.Sort()
 
-	return utils.MakeBuildFactory(func(init utils.BuildInitializer) (DirectoryGlob, error) {
-		return DirectoryGlob{
+	return utils.MakeBuildFactory(func(init utils.BuildInitializer) (DirectoryMatch, error) {
+		return DirectoryMatch{
 			Source:        utils.SafeNormalize(source),
-			IncludedGlobs: includedGlobs,
-			ExcludedGlobs: excludedGlobs,
+			IncludedRe:    includedRe,
+			ExcludedRe:    excludedRe,
 			ExcludedFiles: excludedFiles,
 			Results:       utils.FileSet{},
 		}, nil //init.NeedDirectories(source) // no dependency so to be built every-time
 	})
 }
 
-func (x *DirectoryGlob) GetSourceDirectory() utils.Directory {
+func (x *DirectoryMatch) GetSourceDirectory() utils.Directory {
 	return x.Source
 }
-func (x *DirectoryGlob) Alias() utils.BuildAlias {
+func (x *DirectoryMatch) Alias() utils.BuildAlias {
 	var bb utils.BuildAliasBuilder
 	utils.MakeBuildAliasBuilder(&bb, "UFS", len(x.Source.Path)+1+len(x.Source.Basename())+4)
 
-	bb.WriteString('/', "Glob")
+	bb.WriteString('/', "Match")
 	bb.WriteString('/', x.Source.Path)
 	bb.WriteString('/', x.Source.Basename())
-
-	for i, it := range x.IncludedGlobs {
-		if i == 0 {
-			bb.WriteString('|', it)
-		} else {
-			bb.WriteString(';', it)
-		}
-	}
-
-	for i, it := range x.ExcludedGlobs {
-		if i == 0 {
-			bb.WriteString('|', it)
-		} else {
-			bb.WriteString(';', it)
-		}
-	}
+	bb.WriteString('|', x.IncludedRe.String())
+	bb.WriteString('|', x.ExcludedRe.String())
 
 	for i, it := range x.ExcludedFiles {
 		if i == 0 {
@@ -276,7 +280,7 @@ func (x *DirectoryGlob) Alias() utils.BuildAlias {
 
 	return bb.Alias()
 }
-func (x *DirectoryGlob) Build(bc utils.BuildContext) error {
+func (x *DirectoryMatch) Build(bc utils.BuildContext) error {
 	x.Results = utils.FileSet{}
 
 	if info, err := x.Source.Info(); err == nil {
@@ -285,21 +289,15 @@ func (x *DirectoryGlob) Build(bc utils.BuildContext) error {
 		return err
 	}
 
-	includeRE := utils.MakeGlobRegexp(x.IncludedGlobs...)
-	excludeRE := utils.MakeGlobRegexp(x.ExcludedGlobs...)
-	if !includeRE.Valid() {
-		includeRE = utils.MakeGlobRegexp("*")
-	}
-
 	err := x.Source.MatchFilesRec(func(f utils.Filename) error {
 		f = utils.SafeNormalize(f)
 		if !x.ExcludedFiles.Contains(f) {
-			if !excludeRE.Valid() || !excludeRE.MatchString(f.String()) {
+			if !x.ExcludedRe.Valid() || !x.ExcludedRe.MatchString(f.String()) {
 				x.Results.Append(f)
 			}
 		}
 		return nil
-	}, includeRE)
+	}, x.IncludedRe)
 
 	if err == nil {
 		bc.Annotate(utils.AnnocateBuildCommentf("%d files", len(x.Results)))
@@ -307,10 +305,10 @@ func (x *DirectoryGlob) Build(bc utils.BuildContext) error {
 
 	return err
 }
-func (x *DirectoryGlob) Serialize(ar base.Archive) {
+func (x *DirectoryMatch) Serialize(ar base.Archive) {
 	ar.Serializable(&x.Source)
-	ar.Serializable(&x.IncludedGlobs)
-	ar.Serializable(&x.ExcludedGlobs)
+	ar.Serializable(&x.IncludedRe)
+	ar.Serializable(&x.ExcludedRe)
 	ar.Serializable(&x.ExcludedFiles)
 	ar.Serializable(&x.Results)
 }