diff --git a/R/async-http.R b/R/async-http.R
index 777c1560..08d80dbe 100644
--- a/R/async-http.R
+++ b/R/async-http.R
@@ -316,7 +316,17 @@ download_files <- function(data, ...) {
     row <- data[idx, ]
     dx <- download_if_newer(row$url, row$path, row$etag,
       on_progress = prog_cb, options = list(timeout = row$timeout %||% 100),
-      ...)$
+      ...)
+
+    if ("fallback_url" %in% names(row) && !is.na(row$fallback_url)) {
+      dx <- dx$catch(error = function(err) {
+        download_if_newer(row$fallback_url, row$path, row$etag,
+                          options = list(timeout = row$timeout %||% 10),
+                          ...)
+      })
+    }
+
+    dx <- dx$
       then(function(result) {
         status_code <- result$response$status_code
         if (status_code == 304) {
diff --git a/R/metadata-cache.R b/R/metadata-cache.R
index f0cdf63f..e8faebfd 100644
--- a/R/metadata-cache.R
+++ b/R/metadata-cache.R
@@ -420,6 +420,7 @@ cmc__get_cache_files <- function(self, private, which) {
   repo_enc <- rep(repo_encode(private$repos), each = nrow(private$dirs))
   pkgs_dirs <- rep(private$dirs$contriburl, nrow(private$repos))
   pkgs_files <- file.path(pkgs_dirs, "PACKAGES.gz")
+  pkgs_files2 <- file.path(pkgs_dirs, "PACKAGES")
   mirror <- rep(private$repos$url, each = nrow(private$dirs))
   type <- rep(private$repos$type, each = nrow(private$dirs))
   bioc_version <- rep(private$repos$bioc_version, each = nrow(private$dirs))
@@ -448,6 +449,7 @@ cmc__get_cache_files <- function(self, private, which) {
       base = pkgs_files,
       mirror = mirror,
       url = paste0(mirror, "/", pkgs_files),
+      fallback_url = paste0(mirror, "/", pkgs_files2),
       platform = rep(private$dirs$platform, nrow(private$repos)),
       type = type,
       bioc_version = bioc_version,
@@ -673,6 +675,7 @@ cmc__update_replica_pkgs <- function(self, private) {
   dls <- data.frame(
     stringsAsFactors = FALSE,
     url = c(pkgs$url, pkgs$meta_url[meta]),
+    fallback_url = c(pkgs$fallback_url, rep(NA_character_, sum(meta))),
     path = c(pkgs$path, pkgs$meta_path[meta]),
     etag = c(pkgs$etag, pkgs$meta_etag[meta]),
     timeout = rep(c(200, 100), c(nrow(pkgs), sum(meta))),
diff --git a/tests/testthat/test-metadata-cache.R b/tests/testthat/test-metadata-cache.R
index a9b81b40..a085bf8a 100644
--- a/tests/testthat/test-metadata-cache.R
+++ b/tests/testthat/test-metadata-cache.R
@@ -21,7 +21,7 @@ test_that("get_cache_files", {
     expect_true(tibble::is_tibble(files$pkgs))
     expect_equal(
       sort(names(files$pkgs)),
-      sort(c("path", "etag", "basedir", "base", "mirror", "url",
+      sort(c("path", "etag", "basedir", "base", "mirror", "url", "fallback_url",
              "platform", "type", "bioc_version", "meta_path", "meta_etag",
              "meta_url")))
     expect_equal(