diff --git a/Cargo.toml b/Cargo.toml
index 5180d2a75f..9d7ce46eca 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -131,7 +131,20 @@ missing_safety_doc = "warn" #TODO: set to deny when all safety documentation is
 precedence = "deny"
 
 [patch.crates-io]
-redox_syscall = { git = "https://gitlab.redox-os.org/redox-os/syscall.git" }
+# Red Bear OS Phase I: s2idle / Modern Standby support.
+# The [patch.crates-io] replaces the upstream gitlab.redox-os.org
+# redox_syscall (which lacks the new AcpiVerb::EnterS2Idle /
+# ExitS2Idle variants) with the local fork at
+# local/sources/syscall/ (a sibling directory of base/, both
+# under local/sources/). The local fork is the upstream
+# gitlab.redox-os.org/redox-os/syscall @ 79cb6d9 with our
+# Red Bear OS P1 commit (cfa7f0c) on top. The version field
+# stays at upstream 0.8.1 — periodic rebase via
+# 'git fetch upstream && git rebase upstream/master' is the
+# workflow when upstream changes. Hardware-agnostic — works
+# for any platform with Modern Standby firmware (Dell, HP,
+# Lenovo, LG Gram, etc.).
+redox_syscall = { path = "../syscall" }
 
 [patch."https://gitlab.redox-os.org/redox-os/relibc.git"]
 #redox-ioctl = { path = "../../relibc/source/redox-ioctl" }