diff --git a/build/build-rust/cargo-vendor-std.patch b/build/build-rust/cargo-vendor-std.patch
index 9d05c7153c65..4d5ec198c5cc 100644
--- a/build/build-rust/cargo-vendor-std.patch
+++ b/build/build-rust/cargo-vendor-std.patch
@@ -33,7 +33,7 @@ index 0b14df805..7bc5151a4 100644
 -        .iter()
 -        .map(|&name| {
 -            let source_path = SourceId::for_path(&src_path.join("library").join(name))?;
--            let dep = Dependency::parse(name, None, source_path)?;
+-            let dep = Dependency::parse_no_deprecated(name, None, source_path)?;
 +
 +    // Special std packages should be pulled from `library/` and should be
 +    // prefixed with `rustc-std-workspace-` in certain places.
@@ -66,7 +66,7 @@ index 0b14df805..7bc5151a4 100644
 +                entry.path()
 +            };
 +            let source_path = SourceId::for_path(&path)?;
-+            let dep = Dependency::parse(&name, None, source_path)?;
++            let dep = Dependency::parse_no_deprecated(&name, None, source_path)?;
              Ok(dep)
          })
          .collect::<CargoResult<Vec<_>>>()?;
diff --git a/build/valgrind/cross-architecture.sup b/build/valgrind/cross-architecture.sup
index fd634ee7fd3a..3e3def2d4005 100644
--- a/build/valgrind/cross-architecture.sup
+++ b/build/valgrind/cross-architecture.sup
@@ -149,7 +149,6 @@
    Memcheck:Leak
    match-leak-kinds: definite
    fun:malloc
-   ...
    fun:_ZN3std6thread5local4fast12Key$LT$T$GT$14try_initialize*
    fun:_ZN5style5bloom19StyleBloom$LT$E$GT$3new*
    ...
@@ -159,7 +158,6 @@
    Memcheck:Leak
    match-leak-kinds: definite
    fun:malloc
-   ...
    fun:_ZN3std6thread5local4fast12Key$LT$T$GT$14try_initialize*
    ...
    fun:_ZN5style7sharing26StyleSharingCache$LT$E$GT$3new*
diff --git a/build/valgrind/x86_64-pc-linux-gnu.sup b/build/valgrind/x86_64-pc-linux-gnu.sup
index 2e0ed471626f..d3b587ee00ae 100644
--- a/build/valgrind/x86_64-pc-linux-gnu.sup
+++ b/build/valgrind/x86_64-pc-linux-gnu.sup
@@ -1054,7 +1054,6 @@
 {
    Starting with rust 1.52
    Memcheck:Cond
-   ...
    fun:_ZN5style10properties10shorthands4font10parse_into*
    fun:_ZN5style10properties19PropertyDeclaration10parse_into*
    fun:_ZN5style10properties17declaration_block31parse_property_declaration_list*
diff --git a/mozglue/static/rust/build.rs b/mozglue/static/rust/build.rs
index 0c4cbdb0adfd..328aa2cb3691 100644
--- a/mozglue/static/rust/build.rs
+++ b/mozglue/static/rust/build.rs
@@ -38,7 +38,7 @@ fn main() {
     println!("cargo:rerun-if-changed=wrappers.cpp");
 
     let ver = version().unwrap();
-    let max_oom_hook_version = Version::parse("1.56.0-alpha").unwrap();
+    let max_oom_hook_version = Version::parse("1.55.0-alpha").unwrap();
 
     if ver < max_oom_hook_version {
         println!("cargo:rustc-cfg=feature=\"oom_with_hook\"");
diff --git a/taskcluster/ci/fetch/toolchains.yml b/taskcluster/ci/fetch/toolchains.yml
index 5c132d2474c3..a9814d5c7de5 100644
--- a/taskcluster/ci/fetch/toolchains.yml
+++ b/taskcluster/ci/fetch/toolchains.yml
@@ -474,21 +474,21 @@ clang-trunk:
         repo: https://github.com/llvm/llvm-project
         branch: main
 
-# This revision currently corresponds to rust nightly-2021-06-13,
-# which is the first nightly with the version 1.55.0,
+# This revision currently corresponds to rust nightly-2021-05-02,
+# which is the first nightly with the version 1.54.0,
 # so it should be as close as possible to the behaviour of
-# stable-1.54.0.
+# stable-1.53.0.
 #
 # We use this to build from source, so the resulting non-official
-# artifacts will report their version as "1.55.0-dev", but will otherwise
+# artifacts will report their version as "1.54.0-dev", but will otherwise
 # behave like a nightly build. This means they will allow you to use
 # unstable features like -Zbuild-std and sanitizers.
-rust-1.55.0-dev:
-    description: Rust 1.55.0-dev source code
+rust-1.54.0-dev:
+    description: Rust 1.54.0-dev source code
     fetch:
         type: git
         repo: https://github.com/rust-lang/rust/
-        revision: 24bdc6d73a75dce9a7013ebc7c037013ff4ea099
+        revision: 4de75720970a223b125a811d3662fd15a08d4d18
 
 wasi-sdk:
     description: wasi-sdk source code
diff --git a/taskcluster/ci/toolchain/dump-syms.yml b/taskcluster/ci/toolchain/dump-syms.yml
index 215661c379a9..e117fcc95c28 100644
--- a/taskcluster/ci/toolchain/dump-syms.yml
+++ b/taskcluster/ci/toolchain/dump-syms.yml
@@ -25,7 +25,7 @@ linux64-dump_syms:
         toolchain:
             - linux64-binutils
             - linux64-clang-11
-            - linux64-rust-1.54
+            - linux64-rust-1.53
             - sysroot-x86_64-linux-gnu
 
 macosx64-dump_syms:
@@ -37,7 +37,7 @@ macosx64-dump_syms:
         toolchain-artifact: public/build/dump_syms.tar.xz
     fetches:
         toolchain:
-            - linux64-rust-macos-1.54
+            - linux64-rust-macos-1.53
             - linux64-clang-11
             - linux64-cctools-port-clang-11
             - linux64-llvm-dsymutil
@@ -52,7 +52,7 @@ macosx64-aarch64-dump_syms:
         toolchain-artifact: public/build/dump_syms.tar.xz
     fetches:
         toolchain:
-            - linux64-rust-macos-1.54
+            - linux64-rust-macos-1.53
             - linux64-clang-11
             - linux64-cctools-port-clang-11
             - linux64-llvm-dsymutil
@@ -72,4 +72,4 @@ win64-dump_syms:
         tooltool-downloads: internal
     fetches:
         toolchain:
-            - win64-rust-1.54
+            - win64-rust-1.53
diff --git a/taskcluster/ci/toolchain/rust.yml b/taskcluster/ci/toolchain/rust.yml
index c3596c0a1451..679f294ddb6a 100644
--- a/taskcluster/ci/toolchain/rust.yml
+++ b/taskcluster/ci/toolchain/rust.yml
@@ -44,12 +44,12 @@ linux64-rust-1.51:
         toolchain:
             - linux64-clang
 
-linux64-rust-1.54:
+linux64-rust-1.53:
     treeherder:
         symbol: TL(rust)
     run:
         arguments: [
-            '--channel', '1.54.0',
+            '--channel', '1.53.0',
             '--host', 'x86_64-unknown-linux-gnu',
             '--target', 'x86_64-unknown-linux-gnu',
             '--target', 'i686-unknown-linux-gnu',
@@ -80,19 +80,19 @@ linux64-rust-dev:
         ]
     fetches:
         fetch:
-            - rust-1.55.0-dev
+            - rust-1.54.0-dev
         toolchain:
             - linux64-clang
             - linux64-binutils
 
 
-linux64-rust-cross-1.54:
+linux64-rust-cross-1.53:
     description: "rust repack with macos and windows cross support"
     treeherder:
         symbol: TL(rust-cross)
     run:
         arguments: [
-            '--channel', '1.54.0',
+            '--channel', '1.53.0',
             '--host', 'x86_64-unknown-linux-gnu',
             '--target', 'x86_64-unknown-linux-gnu',
             '--target', 'i686-unknown-linux-gnu',
@@ -109,13 +109,13 @@ linux64-rust-cross-1.54:
         ]
         toolchain-alias: linux64-rust-cross
 
-linux64-rust-static-1.54:
+linux64-rust-static-1.53:
     description: "rust repack with static linking support"
     treeherder:
         symbol: TL(rust-static)
     run:
         arguments: [
-            '--channel', '1.54.0',
+            '--channel', '1.53.0',
             '--host', 'x86_64-unknown-linux-gnu',
             '--target', 'x86_64-unknown-linux-gnu',
             '--target', 'x86_64-unknown-linux-musl',
@@ -161,13 +161,13 @@ linux64-rust-macos-1.51:
             '--target', 'x86_64-apple-darwin',
         ]
 
-linux64-rust-macos-1.54:
+linux64-rust-macos-1.53:
     description: "rust repack with macos-cross support"
     treeherder:
-        symbol: TL(rust-macos-1.54)
+        symbol: TL(rust-macos-1.53)
     run:
         arguments: [
-            '--channel', '1.54.0',
+            '--channel', '1.53.0',
             '--host', 'x86_64-unknown-linux-gnu',
             '--target', 'x86_64-unknown-linux-gnu',
             '--target', 'x86_64-apple-darwin',
@@ -175,13 +175,13 @@ linux64-rust-macos-1.54:
         ]
         toolchain-alias: linux64-rust-macos
 
-linux64-rust-android-1.54:
+linux64-rust-android-1.53:
     description: "rust repack with android-cross support"
     treeherder:
         symbol: TL(rust-android)
     run:
         arguments: [
-            '--channel', '1.54.0',
+            '--channel', '1.53.0',
             '--host', 'x86_64-unknown-linux-gnu',
             '--target', 'x86_64-unknown-linux-gnu',
             '--target', 'armv7-linux-androideabi',
@@ -222,13 +222,13 @@ linux64-rust-windows-1.51:
             '--target', 'i686-pc-windows-msvc',
         ]
 
-linux64-rust-windows-1.54:
+linux64-rust-windows-1.53:
     description: "rust repack with windows-cross support"
     treeherder:
         symbol: TL(rust-win)
     run:
         arguments: [
-            '--channel', '1.54.0',
+            '--channel', '1.53.0',
             '--host', 'x86_64-unknown-linux-gnu',
             '--target', 'x86_64-unknown-linux-gnu',
             '--target', 'x86_64-pc-windows-msvc',
@@ -260,12 +260,12 @@ win64-rust-1.51:
             '--target', 'aarch64-pc-windows-msvc',
         ]
 
-win64-rust-1.54:
+win64-rust-1.53:
     treeherder:
         symbol: TW64(rust)
     run:
         arguments: [
-            '--channel', '1.54.0',
+            '--channel', '1.53.0',
             '--host', 'x86_64-pc-windows-msvc',
             '--target', 'x86_64-pc-windows-msvc',
             '--target', 'i686-pc-windows-msvc',
@@ -273,12 +273,12 @@ win64-rust-1.54:
         ]
         toolchain-alias: win64-rust
 
-macosx64-rust-1.54:
+macosx64-rust-1.53:
     treeherder:
         symbol: TM(rust)
     run:
         arguments: [
-            '--channel', '1.54.0',
+            '--channel', '1.53.0',
             '--host', 'x86_64-apple-darwin',
             '--target', 'x86_64-apple-darwin',
         ]
@@ -297,12 +297,12 @@ mingw32-rust-1.51:
             '--target', 'x86_64-unknown-linux-gnu',
         ]
 
-mingw32-rust-1.54:
+mingw32-rust-1.53:
     treeherder:
         symbol: TMW(rust)
     run:
         arguments: [
-            '--channel', '1.54.0',
+            '--channel', '1.53.0',
             '--host', 'x86_64-unknown-linux-gnu',
             '--target', 'i686-unknown-linux-gnu',
             '--target', 'i686-pc-windows-gnu',