Revert "remove system-skip-chunks image"

This reverts commit 8381ab2.

src/utils/manifest.js

@@ -46,10 +46,19 @@ export class Image {
   constructor(json) {
     this.name = json.name
     this.sparse = json.sparse
-    this.checksum = json.hash
-    this.fileName = `${this.name}-${json.hash_raw}.img`
-    this.archiveUrl = json.url
-    this.size = json.size
+
+    if (this.name === 'system') {
+      this.checksum = json.alt.hash
+      this.fileName = `${this.name}-skip-chunks-${json.hash_raw}.img`
+      this.archiveUrl = json.alt.url
+      this.size = json.alt.size
+    } else {
+      this.checksum = json.hash
+      this.fileName = `${this.name}-${json.hash_raw}.img`
+      this.archiveUrl = json.url
+      this.size = json.size
+    }
+
     this.archiveFileName = this.archiveUrl.split('/').pop()
   }
 }

src/utils/manifest.test.js

@@ -35,8 +35,10 @@ for (const [branch, manifestUrl] of Object.entries(config.manifests)) {
         })
 
         if (image.name === 'system') {
-          test('system image', () => {
-            expect(image.sparse, 'system image to not be sparse').toBe(false)
+          test('alt image', () => {
+            expect(image.sparse, 'system image to be sparse').toBe(true)
+            expect(image.fileName, 'system image to be skip chunks').toContain('-skip-chunks-')
+            expect(image.archiveUrl, 'system image to point to skip chunks').toContain('-skip-chunks-')
           })
         }