diff --git a/local/patches/RcppParallel/bundled-tbb-link-order.patch b/local/patches/RcppParallel/bundled-tbb-link-order.patch
deleted file mode 100644
index 45114a8..0000000
--- a/local/patches/RcppParallel/bundled-tbb-link-order.patch
+++ /dev/null
@@ -1,46 +0,0 @@
-diff --git a/tools/config/configure.R b/tools/config/configure.R
-index 6293fe1..2f84337 100644
---- a/tools/config/configure.R
-+++ b/tools/config/configure.R
-@@ -186,12 +186,23 @@ define(
- )
- 
- # set PKG_LIBS
-+#
-+# bincraft patch: the library directories below are passed as plain '-L', not
-+# '-Wl,-L'. gcc expands its own search dirs (/usr/lib64, /usr/lib/<triplet>)
-+# into explicit '-L' options ahead of anything forwarded verbatim with '-Wl,',
-+# so with '-Wl,-L' a system libtbb.so wins over the one named here: on a build
-+# host with a distro TBB installed, '-ltbb' resolves to that library and
-+# RcppParallel.so records its SONAME (libtbb.so.12, or libtbb.so.2 for the
-+# classic Intel TBB) instead of the bundled 'libtbb.so'. The binary then loads
-+# the system TBB rather than the copy shipped in RcppParallel/lib, and fails
-+# outright on a machine that has no system TBB. gcc places a plain '-L' before
-+# its built-in dirs, so the intended library is found first.
- pkgLibs <- if (!is.na(tbbLib)) {
- 
-    # a TBB supplied via TBB_LIB / TBB_ROOT. an rpath is meaningless on Windows,
-    # where the loader has no equivalent -- see R/zzz.R for how we resolve there
-    c(
--      "-Wl,-L\"$(TBB_LIB)\"",
-+      "-L\"$(TBB_LIB)\"",
-       if (.Platform$OS.type != "windows")
-          sprintf("-Wl,-rpath,%s", shQuote(tbbLib)),
-       "-l$(TBB_NAME)",
-@@ -201,14 +212,14 @@ pkgLibs <- if (!is.na(tbbLib)) {
- } else if (R.version$os == "emscripten") {
- 
-    c(
--      "-Wl,-Ltbb/build/lib_release",
-+      "-Ltbb/build/lib_release",
-       "-l$(TBB_NAME)"
-    )
- 
- } else {
- 
-    c(
--      "-Wl,-Ltbb/build/lib_release",
-+      "-Ltbb/build/lib_release",
-       "-l$(TBB_NAME)",
-       "-l$(TBB_MALLOC_NAME)"
-    )
diff --git a/local/patches/RcppParallel/force-bundled-tbb.patch b/local/patches/RcppParallel/force-bundled-tbb.patch
new file mode 100644
index 0000000..c46a05e
--- /dev/null
+++ b/local/patches/RcppParallel/force-bundled-tbb.patch
@@ -0,0 +1,154 @@
+diff --git a/R/aaa.R b/R/aaa.R
+index 568a2aa..bfdab4c 100644
+--- a/R/aaa.R
++++ b/R/aaa.R
+@@ -5,4 +5,21 @@ TBB_LIB  <- ""
+ TBB_INC  <- ""
+ 
+ TBB_NAME <- "tbb"
+-TBB_MALLOC_NAME <- "tbbmalloc"
+\ No newline at end of file
++TBB_MALLOC_NAME <- "tbbmalloc"
++
++# bincraft patch: our build images (and plenty of user environments) export
++# TBB_ROOT / TBB_LIB / TBB_INC. A binary we publish always carries its own
++# oneTBB in RcppParallel/lib -- see the companion changes in
++# tools/config/configure.R and src/install.libs.R -- so honouring those
++# variables at run time is actively harmful: .onLoad() would dyn.load() a
++# second, unrelated TBB into the process next to the bundled one (two copies
++# of the same symbols in the global scope, which segfaults R on load), and
++# RcppParallelLibs() / CxxFlags() would hand that system TBB to dependents
++# such as rstan, putting NEEDED libtbb.so.12 back into their binaries. Read
++# the variables only when explicitly opted back in.
++bincraftGetenv <- function(name, unset = "") {
++   if (Sys.getenv("BINCRAFT_ALLOW_SYSTEM_TBB", unset = "FALSE") == "TRUE")
++      Sys.getenv(name, unset = unset)
++   else
++      unset
++}
+\ No newline at end of file
+diff --git a/R/tbb.R b/R/tbb.R
+index 6f6a745..e407986 100644
+--- a/R/tbb.R
++++ b/R/tbb.R
+@@ -17,7 +17,7 @@ tbbLibraryPath <- function(name = NULL) {
+    sysname <- Sys.info()[["sysname"]]
+ 
+    # find root for TBB install
+-   tbbRoot <- Sys.getenv("TBB_LIB", unset = tbbRoot())
++   tbbRoot <- bincraftGetenv("TBB_LIB", unset = tbbRoot())
+    if (is.null(name))
+       return(tbbRoot)
+ 
+@@ -58,7 +58,7 @@ tbbCxxFlags <- function() {
+    flags <- c("-DRCPP_PARALLEL_USE_TBB=1")
+ 
+    # if TBB_INC is set, apply those library paths
+-   tbbInc <- Sys.getenv("TBB_INC", unset = TBB_INC)
++   tbbInc <- bincraftGetenv("TBB_INC", unset = TBB_INC)
+    if (!file.exists(tbbInc)) {
+       tbbInc <- system.file("include", package = "RcppParallel")
+    }
+@@ -117,7 +117,7 @@ tbbLdFlags <- function() {
+    }
+ 
+    # shortcut if TBB_LIB defined
+-   tbbLib <- Sys.getenv("TBB_LINK_LIB", Sys.getenv("TBB_LIB", unset = TBB_LIB))
++   tbbLib <- bincraftGetenv("TBB_LINK_LIB", bincraftGetenv("TBB_LIB", unset = TBB_LIB))
+    if (nzchar(tbbLib)) {
+       if (R.version$os == "emscripten") {
+          fmt <- "-L%1$s -l%2$s"
+diff --git a/src/install.libs.R b/src/install.libs.R
+index 3b3cfda..c0e6f3e 100644
+--- a/src/install.libs.R
++++ b/src/install.libs.R
+@@ -477,6 +477,18 @@ prependFlags <- function(prependFlags, toFlags) {
+ tbbLib <- Sys.getenv("TBB_LIB")
+ tbbInc <- Sys.getenv("TBB_INC")
+ 
++# bincraft patch: the companion change in tools/config/configure.R stops an
++# ambient TBB_LIB / TBB_INC from selecting a system TBB, but this script is
++# also run directly by `R CMD INSTALL` (not only through the `tbb` rule in
++# src/Makevars, which passes the configured values), so at install time it
++# still sees the image's environment and would symlink the system libraries
++# into RcppParallel/lib. Drop them here for the same reason, under the same
++# opt-out.
++if (Sys.getenv("BINCRAFT_ALLOW_SYSTEM_TBB", unset = "FALSE") != "TRUE") {
++   tbbLib <- ""
++   tbbInc <- ""
++}
++
+ args <- commandArgs(trailingOnly = TRUE)
+ if (identical(args, "build")) {
+    if (nzchar(tbbLib) && nzchar(tbbInc)) {
+diff --git a/tools/config/configure.R b/tools/config/configure.R
+index 6293fe1..eae4aaa 100644
+--- a/tools/config/configure.R
++++ b/tools/config/configure.R
+@@ -40,6 +40,24 @@ tbbRoot  <- Sys.getenv("TBB_ROOT", unset = NA)
+ tbbLib   <- Sys.getenv("TBB_LIB", unset = NA)
+ tbbInc   <- Sys.getenv("TBB_INC", unset = NA)
+ 
++# bincraft patch: ignore an ambient TBB_ROOT / TBB_LIB / TBB_INC. Several of
++# our build images export these (a leftover from RcppParallel 5.x, whose
++# bundled Intel TBB would not build on musl or with modern g++), and any of
++# them switches the branches below to a system TBB. The published binary then
++# records NEEDED libtbb.so.12 (or libtbb.so.2 for the classic Intel TBB) and
++# gets a RcppParallel/lib full of absolute symlinks into the image's library
++# dir, so it cannot dyn.load on a consumer machine without that exact TBB.
++# 6.x bundles oneTBB 2022 and builds it with cmake on every platform we ship,
++# so the bundled copy is always the right choice here; forcing it in the
++# package rather than relying on the image environment keeps the binary
++# correct whichever image version CI happens to pull. Set
++# BINCRAFT_ALLOW_SYSTEM_TBB=TRUE to restore the upstream behaviour.
++if (Sys.getenv("BINCRAFT_ALLOW_SYSTEM_TBB", unset = "FALSE") != "TRUE") {
++   tbbRoot <- NA
++   tbbLib  <- NA
++   tbbInc  <- NA
++}
++
+ tbbName  <- Sys.getenv("TBB_NAME", unset = "tbb")
+ tbbMallocName <- Sys.getenv("TBB_MALLOC_NAME", unset = "tbbmalloc")
+ 
+@@ -186,12 +204,23 @@ define(
+ )
+ 
+ # set PKG_LIBS
++#
++# bincraft patch: the library directories below are passed as plain '-L', not
++# '-Wl,-L'. gcc expands its own search dirs (/usr/lib64, /usr/lib/<triplet>)
++# into explicit '-L' options ahead of anything forwarded verbatim with '-Wl,',
++# so with '-Wl,-L' a system libtbb.so wins over the one named here: on a build
++# host with a distro TBB installed, '-ltbb' resolves to that library and
++# RcppParallel.so records its SONAME (libtbb.so.12, or libtbb.so.2 for the
++# classic Intel TBB) instead of the bundled 'libtbb.so'. The binary then loads
++# the system TBB rather than the copy shipped in RcppParallel/lib, and fails
++# outright on a machine that has no system TBB. gcc places a plain '-L' before
++# its built-in dirs, so the intended library is found first.
+ pkgLibs <- if (!is.na(tbbLib)) {
+ 
+    # a TBB supplied via TBB_LIB / TBB_ROOT. an rpath is meaningless on Windows,
+    # where the loader has no equivalent -- see R/zzz.R for how we resolve there
+    c(
+-      "-Wl,-L\"$(TBB_LIB)\"",
++      "-L\"$(TBB_LIB)\"",
+       if (.Platform$OS.type != "windows")
+          sprintf("-Wl,-rpath,%s", shQuote(tbbLib)),
+       "-l$(TBB_NAME)",
+@@ -201,14 +230,14 @@ pkgLibs <- if (!is.na(tbbLib)) {
+ } else if (R.version$os == "emscripten") {
+ 
+    c(
+-      "-Wl,-Ltbb/build/lib_release",
++      "-Ltbb/build/lib_release",
+       "-l$(TBB_NAME)"
+    )
+ 
+ } else {
+ 
+    c(
+-      "-Wl,-Ltbb/build/lib_release",
++      "-Ltbb/build/lib_release",
+       "-l$(TBB_NAME)",
+       "-l$(TBB_MALLOC_NAME)"
+    )
diff --git a/local/patches/registry.json b/local/patches/registry.json
index fe0d387..a7e29dd 100644
--- a/local/patches/registry.json
+++ b/local/patches/registry.json
@@ -6,8 +6,8 @@
     "env": {},
     "configure_args": [],
     "makevars": {},
-    "patch": "RcppParallel/bundled-tbb-link-order.patch",
-    "reason": "RcppParallel 6.x bundles oneTBB 2022 and builds it with cmake, which works on musl and g++ 8-15, so the system-TBB workaround needed for 5.x is gone. What remains broken is the link order: configure.R passes the TBB directory as '-Wl,-L', and gcc expands its own search dirs (/usr/lib64, /usr/lib/<triplet>) into '-L' options ahead of anything forwarded with '-Wl,'. On a build host with a distro TBB installed, '-ltbb' therefore resolves to the system library and RcppParallel.so records its SONAME (libtbb.so.12, or libtbb.so.2 for the classic Intel TBB on el8/el9) instead of the bundled 'libtbb.so'. The published binary then loads the system TBB rather than the copy in RcppParallel/lib and fails to dyn.load on a consumer machine without one, the same way fs did with libuv. Passing a plain '-L' puts the bundled build dir ahead of gcc's defaults; verified on alpine 3.24, el8 and ubuntu noble to produce NEEDED libtbb.so + RPATH $ORIGIN/../lib, loading with every system libtbb removed."
+    "patch": "RcppParallel/force-bundled-tbb.patch",
+    "reason": "RcppParallel 6.x bundles oneTBB 2022 and builds it with cmake on every platform we ship, so the system-TBB workaround needed for 5.x is gone, but two things still steer the build back to a system TBB. (1) Ambient TBB_ROOT/TBB_LIB/TBB_INC: several build images still export these (build-env-images dropped them, but the images are rebuilt only by cron/manual runs, so a stale image keeps them), and R reads ~/.Renviron *after* the process environment, so no pipeline-side env override can undo it. configure.R then takes the system-TBB branch, install.libs.R symlinks the image's libraries into RcppParallel/lib as absolute paths, and the binary records NEEDED libtbb.so.12 (libtbb.so.2 for the classic Intel TBB on el8/el9) -- it cannot dyn.load on a consumer machine without that exact TBB. Both files are patched to ignore those variables (opt out with BINCRAFT_ALLOW_SYSTEM_TBB=TRUE); install.libs.R needs it separately because R CMD INSTALL runs it outside the src/Makevars rule that passes the configured values. (2) Link order: the bundled branch passes its build dir as '-Wl,-Ltbb/build/lib_release', and gcc expands its own search dirs (/usr/lib64, /usr/lib/<triplet>) into '-L' options ahead of anything forwarded with '-Wl,', so '-ltbb' would still resolve to a distro TBB when one is installed; a plain '-L' puts the bundled dir first. Verified on the current build-env-ubuntu:jammy image (which still exports TBB_INC/TBB_LIB): NEEDED libtbb.so, RUNPATH $ORIGIN/../lib, real libtbb.so.2 in RcppParallel/lib, and the package loads with every system libtbb moved away."
   },
   {
     "package": "fs",