--- dyld/dyld-1231.3/cache_builder/NewSharedCacheBuilder.cpp
+++ dyld/dyld-1245.1/cache_builder/NewSharedCacheBuilder.cpp
@@ -310,11 +310,14 @@
     if ( !builder )
         return Error("swift_externalMetadataBuilder_create failed");
 
-    for ( const CacheDylib* dylib : this->objcOptimizer.objcDylibs ) {
-        if ( dylib->inputMF == nullptr ) continue;
-
-        if ( const char* err = swift_externalMetadataBuilder_addDylib(builder, dylib->inputMF->installName(),
-                (const struct mach_header*)dylib->inputMF, dylib->inputFile->size) )
+    for ( const CacheDylib& dylib : this->cacheDylibs ) {
+        if ( dylib.inputMF == nullptr ) continue;
+
+        // TODO: rdar://132262275 (dyld shared cache builder should tell Swift Metadata builder also about dyld)
+        if ( dylib.inputMF->isDyld() ) continue;
+
+        if ( const char* err = swift_externalMetadataBuilder_addDylib(builder, dylib.inputMF->installName(),
+                (const struct mach_header*)dylib.inputMF, dylib.inputFile->size) )
             return Error("swift_externalMetadataBuilder_addDylib failed: %s", err);
     }
 
@@ -3049,6 +3052,43 @@
                         break;
                     }
                     case cache_builder::Region::Kind::readOnly:
+                    case cache_builder::Region::Kind::linkedit:
+                    case cache_builder::Region::Kind::unmapped:
+                    case cache_builder::Region::Kind::dynamicConfig:
+                    case cache_builder::Region::Kind::codeSignature:
+                    case cache_builder::Region::Kind::numKinds:
+                        break;
+                }
+            }
+        }
+
+        // Also split the current file so that read-only are in their own files
+        {
+            // Create a new subCache
+            newSubCaches.push_back(SubCache::makeSubCache(options));
+            SubCache& newSubCache = newSubCaches.back();
+
+            // Move all data to the new subCache
+            for ( Region& oldRegion : subCache.regions ) {
+                if ( oldRegion.chunks.empty() )
+                    continue;
+
+                // Move all the data regions, leave the rest
+                switch ( oldRegion.kind ) {
+                    case cache_builder::Region::Kind::text:
+                    case cache_builder::Region::Kind::dataConst:
+                    case cache_builder::Region::Kind::tproConst:
+                    case cache_builder::Region::Kind::data:
+                    case cache_builder::Region::Kind::auth:
+                    case cache_builder::Region::Kind::authConst:
+                    case cache_builder::Region::Kind::tproAuthConst:
+                        // Nothing to do here
+                        break;
+                    case cache_builder::Region::Kind::readOnly:{
+                        Region& newRegion = newSubCache.regions[(uint32_t)oldRegion.kind];
+                        newRegion.chunks = std::move(oldRegion.chunks);
+                        break;
+                    }
                     case cache_builder::Region::Kind::linkedit:
                     case cache_builder::Region::Kind::unmapped:
                     case cache_builder::Region::Kind::dynamicConfig:
@@ -7827,11 +7867,6 @@
     // We must be a largeContiguous cache. Others were dealt with above in the x86_64 and/or sim cases
     assert(this->config.layout.contiguous.has_value());
 
-    // Some caches have a fixed max slide
-    if ( this->config.layout.cacheFixedSlide.has_value() ) {
-        return this->config.layout.cacheFixedSlide.value();
-    }
-
     // Start off making sure we can't slide past the end of the cache
     CacheVMAddress maxVMAddress(0ULL);
     for ( const Region& region : this->subCaches.back().regions ) {