diff --git a/.github/workflows/docker.yml b/.github/workflows/docker.yml
index cc9e3c6faf83..8cb76ca3b3d1 100644
--- a/.github/workflows/docker.yml
+++ b/.github/workflows/docker.yml
@@ -194,21 +194,18 @@ jobs:
           yarn synthetic-chain prepare-build
         working-directory: a3p-integration
 
-      - name: Override the platforms in docker-bake.json
-        run: |
-          jq -n --arg PLATFORMS "$DOCKER_PLATFORMS" \
-            '{"variable": {"PLATFORMS": { "default": ($PLATFORMS | split(",")) }}}' \
-            > ./docker-bake.override.json
-        working-directory: a3p-integration
-
       - name: Save SDK_TAG
         run: echo "SDK_TAG=${{ needs.snapshot.outputs.tag }}" >> $GITHUB_ENV
 
-      - name: Override some Docker tags we don't want
+      - name: Override the docker-bake.json variables
         run: |
-          IMAGE="$REGISTRY/agoric/agoric-sdk"
-          sed -i.bak -e "s%$IMAGE:unreleased%$IMAGE:$SDK_TAG%g" Dockerfile
-          sed -i.bak -e "s%$REGISTRY/agoric/agoric-3-proposals:%$IMAGE:%g" docker-bake.hcl
+          REPOSITORY_COLON="$REGISTRY/agoric/agoric-sdk:"
+          jq -n --arg REPOSITORY_COLON "$REPOSITORY_COLON" \
+            --arg PLATFORMS "$DOCKER_PLATFORMS" \
+            '{"variable": {
+              "PLATFORMS": { "default": ($PLATFORMS | split(",")) },
+              "REPOSITORY_COLON": { "default": $REPOSITORY_COLON },
+            }}' > ./docker-bake.override.json
         working-directory: a3p-integration
 
       - name: Prefix tags
@@ -246,6 +243,7 @@ jobs:
             docker-bake.override.json
             docker-bake.hcl
             ${{ steps.meta.outputs.bake-file }}
+          set: '*.args.SDK_TAG=${{ env.SDK_TAG }}'
           targets: use-upgrade-next
           push: true
           workdir: ./a3p-integration
diff --git a/a3p-integration/.yarn/patches/@agoric-synthetic-chain-npm-0.1.0-148de716a6.patch b/a3p-integration/.yarn/patches/@agoric-synthetic-chain-npm-0.1.0-148de716a6.patch
index 3d01386399df..a52568daab00 100644
--- a/a3p-integration/.yarn/patches/@agoric-synthetic-chain-npm-0.1.0-148de716a6.patch
+++ b/a3p-integration/.yarn/patches/@agoric-synthetic-chain-npm-0.1.0-148de716a6.patch
@@ -1,5 +1,5 @@
 diff --git a/dist/upgrade-test-scripts/env_setup.sh b/dist/upgrade-test-scripts/env_setup.sh
-index 617a0fbe7efdfa457e28fc52806dba1b323930d8..25f52a6cf133dca830bd0dcd47c91700e6a8effe 100755
+index 53bad1db0fcafa8a64727fe635ba6fdfac63a464..7eea07fc5fa5f4b4221d04fafa28ea3aaacce858 100755
 --- a/dist/upgrade-test-scripts/env_setup.sh
 +++ b/dist/upgrade-test-scripts/env_setup.sh
 @@ -100,7 +100,7 @@ killAgd() {
@@ -11,3 +11,145 @@ index 617a0fbe7efdfa457e28fc52806dba1b323930d8..25f52a6cf133dca830bd0dcd47c91700
  }
  
  provisionSmartWallet() {
+diff --git a/dist/cli/cli.js b/dist/cli/cli.js
+index 53bad1db0fcafa8a64727fe635ba6fdfac63a464..7eea07fc5fa5f4b4221d04fafa28ea3aaacce858 100755
+--- a/dist/cli/cli.js
++++ b/dist/cli/cli.js
+@@ -14,7 +14,9 @@ import path from "node:path";
+ var defaultConfig = {
+   // Tag of the agoric-3 image containing all passed proposals
+   // Must match the Bake file and CI config
+-  fromTag: "latest"
++  fromTag: "latest",
++  repositoryColon: "ghcr.io/agoric/agoric-3-proposals:",
++  sdkRepositoryColon: "ghcr.io/agoric/agoric-sdk:",
+ };
+ function readBuildConfig(root2) {
+   const packageJsonPath = path.join(root2, "package.json");
+@@ -64,7 +66,6 @@ import fs3 from "node:fs";
+ import assert from "node:assert";
+ import fs2 from "node:fs";
+ import * as path2 from "node:path";
+-var repository = "ghcr.io/agoric/agoric-3-proposals";
+ function readInfo(proposalPath) {
+   assert(
+     proposalPath === proposalPath.toLowerCase(),
+@@ -106,7 +107,7 @@ function readProposals(proposalsParent) {
+ function imageNameForProposal(proposal, stage2) {
+   const target = `${stage2}-${proposal.proposalName}`;
+   return {
+-    name: `${repository}:${target}`,
++    name: `${repositoryColon}${target}`,
+     target
+   };
+ }
+@@ -141,10 +142,10 @@ RUN /usr/src/upgrade-test-scripts/run_prepare_zero.sh
+    * Resume from state of an existing image.
+    * Creates a "use" stage upon which a PREPARE or EVAL can stack.
+    */
+-  RESUME(fromTag) {
++  RESUME(fromTag, repositoryColon) {
+     return `
+ ## RESUME
+-FROM ghcr.io/agoric/agoric-3-proposals:${fromTag} as use-${fromTag}
++FROM ${repositoryColon}${fromTag} as use-${fromTag}
+ `;
+   },
+   /**
+@@ -184,10 +185,10 @@ RUN ./run_prepare.sh ${path5}
+     planName,
+     proposalName,
+     sdkImageTag
+-  }) {
++  }, sdkRepositoryColon) {
+     return `
+ # EXECUTE ${proposalName}
+-FROM ghcr.io/agoric/agoric-sdk:${sdkImageTag} as execute-${proposalName}
++FROM ${sdkRepositoryColon}${sdkImageTag} as execute-${proposalName}
+ 
+ WORKDIR /usr/src/upgrade-test-scripts
+ 
+@@ -274,7 +275,7 @@ FROM ${useImage} as latest
+ `;
+   }
+ };
+-function writeBakefileProposals(allProposals2, platforms) {
++function writeBakefileProposals(allProposals2, platforms, repositoryColon) {
+   const json = {
+     variable: {
+       PLATFORMS: {
+@@ -282,16 +283,19 @@ function writeBakefileProposals(allProposals2, platforms) {
+       },
+       PROPOSALS: {
+         default: allProposals2.map((p) => p.proposalName)
+-      }
++      },
++      REPOSITORY_COLON: {
++        default: repositoryColon
++      },
+     }
+   };
+   fs3.writeFileSync("docker-bake.json", JSON.stringify(json, null, 2));
+ }
+-function writeDockerfile(allProposals2, fromTag) {
++function writeDockerfile(allProposals2, fromTag, repositoryColon, sdkRepositoryColon) {
+-  const blocks = ["# syntax=docker/dockerfile:1.4"];
++  const blocks = ["# syntax=docker/dockerfile:1.4\nARG SDK_TAG";
+   let previousProposal = null;
+   if (fromTag) {
+-    blocks.push(stage.RESUME(fromTag));
++    blocks.push(stage.RESUME(fromTag, repositoryColon));
+     previousProposal = {
+       proposalName: fromTag,
+       proposalIdentifier: fromTag,
+@@ -320,7 +324,7 @@ function writeDockerfile(allProposals2, fromTag) {
+             stage.PREPARE_ZERO(proposal.proposalName, proposal.planName)
+           );
+         }
+-        blocks.push(stage.EXECUTE(proposal));
++        blocks.push(stage.EXECUTE(proposal, sdkRepositoryColon));
+         break;
+       default:
+         throw new Error(`unsupported proposal type ${proposal.type}`);
+@@ -476,8 +480,8 @@ var prepareDockerBuild = () => {
+   const cliPath = new URL(import.meta.url).pathname;
+   const publicDir = path4.resolve(cliPath, "..", "..");
+   execSync4(`cp -r ${path4.resolve(publicDir, "docker-bake.hcl")} .`);
+-  writeDockerfile(allProposals, buildConfig.fromTag);
+-  writeBakefileProposals(allProposals, buildConfig.platforms);
++  writeDockerfile(allProposals, buildConfig.fromTag, buildConfig.repositoryColon, buildConfig.sdkRepositoryColon);
++  writeBakefileProposals(allProposals, buildConfig.platforms, buildConfig.repositoryColon);
+   execSync4(`cp -r ${path4.resolve(publicDir, "upgrade-test-scripts")} .`);
+   buildProposalSubmissions(proposals);
+   execSync4(
+diff --git a/dist/docker-bake.hcl b/dist/docker-bake.hcl
+index 75d25cb8e071473b18cc9ea9517b6f4e59f17518..7f54a014b517f82b224e4ec9af68ca55e392b90b 100644
+--- a/dist/docker-bake.hcl
++++ b/dist/docker-bake.hcl
+@@ -23,7 +23,7 @@ target "use" {
+     proposal = PROPOSALS
+   }
+   // TODO proposal *number* would be immutable
+-  tags = ["ghcr.io/agoric/agoric-3-proposals:use-${proposal}"]
++  tags = ["${REPOSITORY_COLON}use-${proposal}"]
+   labels = {
+     "org.opencontainers.image.title": "Use ${proposal}",
+     "org.opencontainers.image.description": "Use agoric-3 synthetic chain after ${proposal} proposal",
+@@ -37,7 +37,7 @@ target "test" {
+   matrix = {
+     proposal = PROPOSALS
+   }
+-  tags = ["ghcr.io/agoric/agoric-3-proposals:test-${proposal}"]
++  tags = ["${REPOSITORY_COLON}test-${proposal}"]
+   labels = {
+     "org.opencontainers.image.title": "Test ${proposal}",
+   }
+@@ -49,7 +49,7 @@ target "test" {
+ target "latest" {
+   inherits = ["docker-metadata-action"]
+   platforms = PLATFORMS
+-  tags = ["ghcr.io/agoric/agoric-3-proposals:latest"]
++  tags = ["${REPOSITORY_COLON}latest"]
+   labels = {
+     "org.opencontainers.image.title": "All passed proposals",
+     "org.opencontainers.image.description": "Use agoric-3 synthetic chain including all passed proposals",
diff --git a/a3p-integration/proposals/e:upgrade-next/package.json b/a3p-integration/proposals/e:upgrade-next/package.json
index c3bd2a7c3c10..5d9f7b8b4356 100644
--- a/a3p-integration/proposals/e:upgrade-next/package.json
+++ b/a3p-integration/proposals/e:upgrade-next/package.json
@@ -1,7 +1,7 @@
 {
   "agoricProposal": {
     "releaseNotes": false,
-    "sdkImageTag": "unreleased",
+    "sdkImageTag": "${SDK_TAG:-unreleased}",
     "planName": "UNRELEASED_A3P_INTEGRATION",
     "upgradeInfo": {
       "coreProposals": []
diff --git a/a3p-integration/yarn.lock b/a3p-integration/yarn.lock
index c5c8e80616e2..6ed90292caea 100644
--- a/a3p-integration/yarn.lock
+++ b/a3p-integration/yarn.lock
@@ -21,7 +21,7 @@ __metadata:
 
 "@agoric/synthetic-chain@patch:@agoric/synthetic-chain@npm%3A0.1.0#~/.yarn/patches/@agoric-synthetic-chain-npm-0.1.0-148de716a6.patch":
   version: 0.1.0
-  resolution: "@agoric/synthetic-chain@patch:@agoric/synthetic-chain@npm%3A0.1.0#~/.yarn/patches/@agoric-synthetic-chain-npm-0.1.0-148de716a6.patch::version=0.1.0&hash=4a65eb"
+  resolution: "@agoric/synthetic-chain@patch:@agoric/synthetic-chain@npm%3A0.1.0#~/.yarn/patches/@agoric-synthetic-chain-npm-0.1.0-148de716a6.patch::version=0.1.0&hash=1011e4"
   dependencies:
     "@endo/zip": "npm:^1.0.1"
     better-sqlite3: "npm:^9.4.0"
@@ -29,7 +29,7 @@ __metadata:
     execa: "npm:^8.0.1"
   bin:
     synthetic-chain: dist/cli/cli.js
-  checksum: 10c0/e974038161b1a9570912a02d9366c6680bc13ee3dfd0e49d06e5ce5e93dbcddf04d1d4cd453af0969bf29ccfe96ce3e141a214539722449add90b13f0785f1f7
+  checksum: 10c0/449353e825da1885d174d44f9de2e8fc8a628a2b1d245ba8107c73743c4b7128ddba5a088f18c18d892f235851f17c4607e3a667c860ac7a55210b8870fe9bae
   languageName: node
   linkType: hard