diff --git a/editor/deploy.ts b/editor/deploy.ts
index ced52bfb..21288926 100644
--- a/editor/deploy.ts
+++ b/editor/deploy.ts
@@ -63,7 +63,9 @@ const rbfTemplate = `
 export function deployCoreAsync(resp: pxtc.CompileResult) {
     let w: pxt.editor.Ev3Wrapper
 
-    let filename = resp.downloadFileBaseName || "pxt"
+    const origElfUF2 = UF2.parseFile(pxt.U.stringToUint8Array(ts.pxtc.decodeBase64(resp.outfiles[pxt.outputName()])))
+    
+    let filename = resp.downloadFileBaseName || (origElfUF2[0].filename || "").replace(/^Projects\//, "").replace(/\.elf$/, "") || "pxt"
     filename = filename.replace(/^lego-/, "")
 
     let fspath = "../prjs/BrkProg_SAVE/"
@@ -77,8 +79,6 @@ export function deployCoreAsync(resp: pxtc.CompileResult) {
     let rbfBIN = pxt.U.fromHex(rbfHex)
     pxt.HF2.write16(rbfBIN, 4, rbfBIN.length)
 
-    let origElfUF2 = UF2.parseFile(pxt.U.stringToUint8Array(ts.pxtc.decodeBase64(resp.outfiles[pxt.outputName()])))
-
     let mkFile = (ext: string, data: Uint8Array = null) => {
         let f = UF2.newBlockFile()
         f.filename = "Projects/" + filename + ext