diff --git a/Gemfile b/Gemfile
index 555c674a31..294e4980ef 100644
--- a/Gemfile
+++ b/Gemfile
@@ -17,7 +17,7 @@ gem 'coder'
 gem 'connection_pool'
 gem 'faraday'
 gem 'faraday_middleware'
-gem 'jemalloc', git: gh('joshk/jemalloc-rb')
+gem 'jemalloc', git: gh('travis-ci/jemalloc-rb')
 gem 'jwt', '~> 1.5'
 gem 'metriks', '0.9.9.6'
 gem 'metriks-librato_metrics', git: gh('eric/metriks-librato_metrics')
diff --git a/Gemfile.lock b/Gemfile.lock
index 3729342936..cc6fd36552 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -6,10 +6,10 @@ GIT
       metriks (>= 0.9.9.6)
 
 GIT
-  remote: https://github.com/joshk/jemalloc-rb
-  revision: 8c9dbef98f6bd4f96b371ec336b7e0c4fdc02d49
+  remote: https://github.com/travis-ci/jemalloc-rb
+  revision: e9528e26aff663efa2c124cdeca47700e389097d
   specs:
-    jemalloc (1.4.5)
+    jemalloc (1.0.2)
 
 GIT
   remote: https://github.com/travis-ci/travis-github_apps
diff --git a/lib/travis/vcs/git/clone.rb b/lib/travis/vcs/git/clone.rb
index 870cb480e8..076325bc7a 100644
--- a/lib/travis/vcs/git/clone.rb
+++ b/lib/travis/vcs/git/clone.rb
@@ -8,6 +8,12 @@ class Clone < Struct.new(:sh, :data)
         def apply
           sh.fold 'git.checkout' do
             sh.export 'GIT_LFS_SKIP_SMUDGE', '1' if lfs_skip_smudge?
+            sh.cmd 'ssh-keygen -R github.com >/dev/null 2>&1 || true', echo: false
+            sh.file '~/.ssh/known_hosts', <<~EOF, append: true, echo: false
+              github.com ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIOMqqnkVzrm0SdG6UOoqKLsabgH5C9okWi0dh2l9GKJl
+              github.com ecdsa-sha2-nistp256 AAAAE2VjZHNhLXNoYTItbmlzdHAyNTYAAAAIbmlzdHAyNTYAAABBBEmKSENjQEezOmxkZMy7opKgwFB9nkt5YRrYMjNuG5N87uRgg6CLrbo5wAdT/y6v0mKV0U2w0WZ2YB/++Tpockg=
+              github.com ssh-rsa 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
+            EOF
             clone_or_fetch
             sh.cd dir
             fetch_ref if fetch_ref?