diff --git a/.github/workflows/coverage.yml b/.github/workflows/coverage.yml
index ba56cde1f00..5f111fd5d24 100644
--- a/.github/workflows/coverage.yml
+++ b/.github/workflows/coverage.yml
@@ -21,6 +21,9 @@ env:
   RUST_LIB_BACKTRACE: 1
   RUST_LOG: info
   COLORBT_SHOW_HIDDEN: 1
+  # Mirror the cfgs in .cargo/config.toml: RUSTFLAGS/RUSTDOCFLAGS replace the
+  # config's rustflags rather than adding to them, compiling out NU7/ZSA code.
+  ZEBRA_CFGS: '--cfg zcash_unstable="nu7" --cfg feature="tx_v6"'
 
 jobs:
   changes:
@@ -57,6 +60,7 @@ jobs:
           persist-credentials: false
       - uses: actions-rust-lang/setup-rust-toolchain@46268bd060767258de96ed93c1251119784f2ab6 #v1.16.1
         with:
+          rustflags: '-D warnings ${{ env.ZEBRA_CFGS }}'
           toolchain: stable
           components: llvm-tools-preview
           cache-on-failure: true
diff --git a/.github/workflows/lint.yml b/.github/workflows/lint.yml
index cc32f60cb08..a3d3709f371 100644
--- a/.github/workflows/lint.yml
+++ b/.github/workflows/lint.yml
@@ -22,6 +22,9 @@ permissions:
 
 env:
   CLICOLOR: 1
+  # Mirror the cfgs in .cargo/config.toml: RUSTFLAGS/RUSTDOCFLAGS replace the
+  # config's rustflags rather than adding to them, compiling out NU7/ZSA code.
+  ZEBRA_CFGS: '--cfg zcash_unstable="nu7" --cfg feature="tx_v6"'
 
 jobs:
   changes:
@@ -70,6 +73,7 @@ jobs:
           persist-credentials: false
       - uses: actions-rust-lang/setup-rust-toolchain@46268bd060767258de96ed93c1251119784f2ab6 #v1.16.1
         with:
+          rustflags: '-D warnings ${{ env.ZEBRA_CFGS }}'
           components: clippy
           toolchain: ${{ matrix.rust-version }}
           cache-on-failure: true
@@ -91,6 +95,7 @@ jobs:
           persist-credentials: false
       - uses: actions-rust-lang/setup-rust-toolchain@46268bd060767258de96ed93c1251119784f2ab6 #v1.16.1
         with:
+          rustflags: '-D warnings ${{ env.ZEBRA_CFGS }}'
           cache-on-failure: true
       - uses: taiki-e/install-action@65851e10cd6c377f11a60e600abc07cb08643468 #v2.79.3
         with:
@@ -99,7 +104,7 @@ jobs:
       - run: cargo hack check --workspace
 
   msrv:
-    name: MSRV
+    name: MSRV (nu7=${{ matrix.nu7 }})
     needs: changes
     if: needs.changes.outputs.lint == 'true'
     permissions:
@@ -109,7 +114,13 @@ jobs:
     runs-on: ubuntu-latest
     timeout-minutes: 30
     strategy:
+      # Both legs run to completion: they check different code, and the two
+      # configurations fail independently.
+      fail-fast: false
       matrix:
+        nu7:
+          - true
+          - false
         include:
           - binary: zebrad
     steps:
@@ -118,7 +129,11 @@ jobs:
           persist-credentials: false
       - uses: actions-rust-lang/setup-rust-toolchain@46268bd060767258de96ed93c1251119784f2ab6 #v1.16.1
         with:
+          # The nu7=false leg is the only job that still checks the MSRV build
+          # without the ZSA code paths, which is what upstream compiles.
+          rustflags: ${{ matrix.nu7 && format('-D warnings {0}', env.ZEBRA_CFGS) || '-D warnings' }}
           toolchain: 1.91 # MSRV
+          cache-key: msrv-nu7-${{ matrix.nu7 }}
           cache-on-failure: true
       - uses: ./.github/actions/setup-zebra-build
       - run: cargo build --bin "${{ matrix.binary }}" --workspace
@@ -138,6 +153,7 @@ jobs:
           persist-credentials: false
       - uses: actions-rust-lang/setup-rust-toolchain@46268bd060767258de96ed93c1251119784f2ab6 #v1.16.1
         with:
+          rustflags: '-D warnings ${{ env.ZEBRA_CFGS }}'
           toolchain: nightly
           cache-on-failure: true
       - uses: ./.github/actions/setup-zebra-build
@@ -146,7 +162,7 @@ jobs:
           # Keep in sync with ./book.yml:jobs.build
           # The -A and -W settings must be the same as the `rustdocflags` in:
           # https://github.com/ZcashFoundation/zebra/blob/main/.cargo/config.toml#L87
-          RUSTDOCFLAGS: --html-in-header katex-header.html -A rustdoc::private_intra_doc_links -D warnings
+          RUSTDOCFLAGS: --html-in-header katex-header.html -A rustdoc::private_intra_doc_links -D warnings ${{ env.ZEBRA_CFGS }}
 
   fmt:
     name: fmt
@@ -184,6 +200,7 @@ jobs:
           persist-credentials: false
       - uses: actions-rust-lang/setup-rust-toolchain@46268bd060767258de96ed93c1251119784f2ab6 #v1.16.1
         with:
+          rustflags: '-D warnings ${{ env.ZEBRA_CFGS }}'
           # TODO: QED-it temp nightly pin: matches Zebra v4.2.0 CI test period; remove before upstream merge.
           toolchain: nightly-2026-03-06
           cache-on-failure: true
@@ -237,7 +254,7 @@ jobs:
       - uses: ./.github/actions/setup-zebra-build
       - run: cargo hack check --all
         env:
-          RUSTFLAGS: -D warnings
+          RUSTFLAGS: -D warnings ${{ env.ZEBRA_CFGS }}
 
   check-cargo-lock:
     name: check-cargo-lock
@@ -254,6 +271,7 @@ jobs:
           persist-credentials: false
       - uses: actions-rust-lang/setup-rust-toolchain@46268bd060767258de96ed93c1251119784f2ab6 #v1.16.1
         with:
+          rustflags: '-D warnings ${{ env.ZEBRA_CFGS }}'
           toolchain: stable
           cache-on-failure: true
       - uses: ./.github/actions/setup-zebra-build
diff --git a/.github/workflows/test-crates.yml b/.github/workflows/test-crates.yml
index c6e829991b1..5fc81d55605 100644
--- a/.github/workflows/test-crates.yml
+++ b/.github/workflows/test-crates.yml
@@ -27,6 +27,9 @@ env:
   RUST_LIB_BACKTRACE: 1
   RUST_LOG: info
   COLORBT_SHOW_HIDDEN: 1
+  # Mirror the cfgs in .cargo/config.toml: RUSTFLAGS/RUSTDOCFLAGS replace the
+  # config's rustflags rather than adding to them, compiling out NU7/ZSA code.
+  ZEBRA_CFGS: '--cfg zcash_unstable="nu7" --cfg feature="tx_v6"'
 
 jobs:
   changes:
@@ -118,6 +121,7 @@ jobs:
 
       - uses: actions-rust-lang/setup-rust-toolchain@46268bd060767258de96ed93c1251119784f2ab6 #v1.16.1
         with:
+          rustflags: '-D warnings ${{ env.ZEBRA_CFGS }}'
           # TODO: QED-it temp Rust 1.94 pin: stable for Zebra v4.2.0 CI; remove before upstream merge.
           toolchain: "1.94"
           components: clippy
@@ -182,6 +186,7 @@ jobs:
 
       - uses: actions-rust-lang/setup-rust-toolchain@46268bd060767258de96ed93c1251119784f2ab6 #v1.16.1
         with:
+          rustflags: '-D warnings ${{ env.ZEBRA_CFGS }}'
           toolchain: ${{ steps.msrv.outputs.version }}
           components: clippy
           cache-key: crate-build-msrv-${{ matrix.crate }}