BMS Firmware Version-Control & Rollback SOP — Corridor CN → QA

Document type: Process / SOP  |  Vertical: EVSE  |  Equipment scope: Battery Management System (BMS) firmware on EVSE-integrated energy storage modules  |  Corridor: CN manufacturing line → QA acceptance site  |  Owner team: TradVolt Engineering Operations

Scope statement. This SOP defines how TradVolt pins, ships, accepts, and rolls back BMS firmware across the CN manufacturing line and the QA acceptance site. It applies to every BMS firmware release shipped on EVSE hardware after 2026-01-01. The procedure does not cover wire-out communications firmware, charger-side firmware, or vehicle-side ECUs. [Claim — internal scope policy]

1. Step sequence

Step #ActionOwnerInput docOutput docDone-when
1Receive firmware release package (signed artifact, OEM release note, SHA-256 checksum) from the firmware supplier.QA LeadOEM release note, signed firmware packageInbound receipt log entrySHA-256 of artifact matches the OEM release note and the receipt log is signed.
2Stage the artifact in the version-control vault, assign a semantic version tag, and freeze dependencies.Release EngineerSigned firmware packageVersion vault record, pinned version tagVersion tag is immutable and visible in the version registry.
3Flash the pinned firmware on the golden BMS unit and run the bench regression checklist (cell balancing, SOC accuracy, CAN diagnostics).Test EngineerPinned firmware, bench regression checklist BMS-REGR-CHECKLIST-v3.pdfBench regression reportAll bench checklist items pass and the report is countersigned by the Test Engineer.
4Issue the line build instruction with the pinned version to the CN production line.Process EngineerApproved version pin, line build instruction templateLine build instruction LBI-CN-BMS-XXXX.pdfLine build instruction is acknowledged by the CN line supervisor.
5Program every BMS module in the CN line and record the firmware version on each traveler.CN Line OperatorLine build instruction, traveler sheetTraveler sheet with version column100% of travelers in that unit carry the pinned firmware version.
6Pack units with the firmware version manifest and prepare shipment under the named Incoterm to the QA acceptance site.Logistics OperatorTraveler sheet, packing list, version manifestShipment file with Incoterm, version manifestVersion manifest is attached and the Incoterm code matches the sales contract.
7Receive units at the QA acceptance site and verify firmware version on each unit; run acceptance sampling per ISO 2859-1.QA InspectorShipment file, AQL sampling planIncoming inspection reportSampling result is recorded and lot disposition is set.
8Sign off the accepted lot and update the version registry with the production tag.QA LeadIncoming inspection reportVersion registry update, lot release noteLot release note is filed and the version registry shows the production tag.
9Detect a regression in service and log a ticket with stack traces, installed firmware version, and unit serial range.Field EngineerService ticket, diagnostic log dumpRegression ticket with evidence packTicket is categorised as firmware regression and routed to Engineering Manager.
10Authorise the rollback to the previously pinned good version recorded in the version registry.Engineering ManagerRegression ticket, version registryRollback authorisation recordAuthorisation record names the target pinned version and the affected serial range.
11Flash the pinned firmware on affected units and run the rollback checklist BMS-ROLLBACK-CHECKLIST-v2.pdf.Service TechnicianPinned firmware, rollback checklistRollback service reportAll checklist items pass and the unit reports the pinned version.
12Append the rollback event to the audit log and notify QA to close the original ticket.Release EngineerRollback service reportAudit log entry, closed ticketAudit log entry is timestamped and QA confirms ticket closure.

2. Roles & responsibilities (RACI summary)

RolePrimary responsibility in this SOP
QA LeadReceives firmware package, signs off accepted lots.
Release EngineerStages firmware in version-control vault, maintains audit log.
Test EngineerRuns bench regression on golden unit.
Process EngineerIssues line build instruction.
CN Line OperatorPrograms BMS modules, records version on traveler.
Logistics OperatorPacks units, attaches version manifest, ships under Incoterm.
QA InspectorRuns ISO 2859-1 acceptance sampling on incoming lots.
Field EngineerLogs regression tickets from service.
Engineering ManagerAuthorises rollbacks.
Service TechnicianExecutes rollback flash and checklist.

3. Document checklist (files to keep on record)

4. Timeline & dependencies

PhaseDepends onIndicative duration
Receive & verify OEM release (Step 1)OEM release package available0.5 working day (indicative)
Stage & pin in vault (Step 2)Step 1 complete0.5 working day (indicative)
Bench regression (Step 3)Step 2 complete, golden unit available1 working day (indicative)
Line build instruction (Step 4)Step 3 pass0.5 working day (indicative)
CN line programming (Step 5)Step 4 issued, CN line slot booked1-2 working days per build lot (indicative)
Shipment CN → QA (Step 6)Step 5 complete, Incoterm defined in sales contractUNCERTAIN — depends on Incoterm and lane
Incoming inspection at QA (Step 7)Step 6 delivery1 working day per lot (indicative)
Lot sign-off (Step 8)Step 7 pass0.5 working day (indicative)
Regression detection (Step 9)Field report, unit serial range0.5 working day (indicative)
Rollback authorisation (Step 10)Step 9 ticket triaged0.5 working day (indicative)
Rollback flash & verify (Step 11)Step 10 authorised, technician dispatched0.5-1 working day per site visit (indicative)
Audit log update (Step 12)Step 11 report filed0.25 working day (indicative)
Lead-time notice. All lead-times labelled "indicative" are planning figures derived from TradVolt's internal SOP review and are subject to OEM release cadence, CN line slot availability, customs clearance times, and the Incoterm named in the underlying sales contract. Treat every figure in this table as UNCERTAIN until confirmed on the active quotation. [Claim — internal SOP draft, dated 2026-09-21]

5. Acceptance sampling reference

Incoming inspection at the QA acceptance site uses an attribute single-sampling plan drawn from ISO 2859-1. The AQL class, inspection level, and accept/reject numbers are defined per contract in AQL-PLAN-BMS-v2.pdf; this SOP does not hardcode AQL values here. [Claim — ISO 2859-1 sampling reference, Src: ISO 2859-1, URL: https://www.iso.org/standard/1141.html, accessed 2026-09-21]

6. Incoterms reference

The shipment from the CN manufacturing site to the QA acceptance site is executed under the Incoterm named in the active sales contract (commonly EXW, FCA, FOB, CIP, or DAP depending on the corridor). Cost transfer, risk transfer, and customs responsibility follow ICC Incoterms 2020 definitions. The Incoterm code is recorded on the shipment manifest and on the version manifest. [Claim — Incoterms definition, Src: ICC Incoterms 2020, URL: https://iccwbo.org/business-solutions/incoterms-rules/incoterms-2020/, accessed 2026-09-21]

7. Duty / HS code block

Disclaimer. The HS code, import duty rate, and VAT/GST rate shown above are intentionally marked "PENDING — lookup" and must be confirmed on the official customs and tax portals of the importing country at the time of each shipment. TradVolt does not provide duty or tax advice; consult a licensed customs broker in the importing jurisdiction. This block is informational only and does not constitute a customs declaration.

8. Compliance & standards references

9. Cost slots

The line items below are cost slots only. TradVolt does not publish fixed prices on this SOP; final pricing is confirmed on the active quotation.

10. CTAs & downloads

Request Quote — replies in 48h Download BMS regression checklist (PDF)

Both links above are live CTAs on tradvolt.com; if either fails to resolve, contact [email protected] for the current artifact.

11. Claim-row references

  1. [Claim — OEM service manual reference | Src: OEM service manual for BMS hardware revision in scope | URL: see active contract folder | accessed 2026-09-21]
  2. [Claim — IEC 61851-1 reference | Src: IEC 61851-1 | URL: https://webstore.iec.ch/publication/33644 | accessed 2026-09-21]
  3. [Claim — UL 1973 reference | Src: UL 1973 | URL: https://www.shopulstandards.com/ProductDetail.aspx?UniqueKey=36484 | accessed 2026-09-21]
  4. [Claim — ISO 2859-1 sampling reference | Src: ISO 2859-1 | URL: https://www.iso.org/standard/1141.html | accessed 2026-09-21]
  5. [Claim — Incoterms definition | Src: ICC Incoterms 2020 | URL: https://iccwbo.org/business-solutions/incoterms-rules/incoterms-2020/ | accessed 2026-09-21]
  6. [Claim — HS classification to be confirmed | Src: WCO Harmonized System | URL: https://www.wcoomd.org/en/topics/nomenclature/instrument-and-tools/hs-nomenclature-2022-edition.aspx | accessed 2026-09-21]
  7. [Claim — China customs portal | Src: China General Administration of Customs | URL: http://english.customs.gov.cn/ | accessed 2026-09-21]
  8. [Claim — EU TARIC consultation | Src: European Commission TARIC | URL: https://ec.europa.eu/taxation_customs/dds2/taric/taric_consultation.jsp | accessed 2026-09-21]
  9. [Claim — FIATA documentation reference | Src: FIATA | URL: https://fiata.org/ | accessed 2026-09-21]
  10. [Claim — CE conformity reference | Src: EU CE marking portal | URL: https://single-market-economy.ec.europa.eu/single-market/ce-marking_en | accessed 2026-09-21]

© TradVolt. This page is a process / SOP draft for EVSE service teams. It does not constitute customs, tax, or legal advice. HS codes, duty rates, and lead-times must be confirmed against the official customs and tax portals of the importing country at the time of each shipment. Last reviewed: 2026-09-21.