AC6 OS Tuning Guide: Regulation 1.09.1 Upgrade Order
Current as of Regulation Ver. 1.09.1 (the 2026-09-18 PS4/PS5 update kept 1.09.1 and only strengthened network security, per the official notice).
Short answer: OS Tuning is a chip-budget game. A first playthrough gives you 98 OST Chips, while maxing every entry takes roughly 197, so you cannot buy everything until New Game+. Spend in this order: the cheap system unlocks (Boost Kick, Quick Turn, Weapon Bay) plus Assault Armor for 5 chips, then the damage line that matches your main weapon type, Direct Hit Modifier, ACS damage reduction, and finally Repair Kits. That plan uses 92 of your first 98 chips.
One caveat up front: the numbers come from community wikis that copy the in-game menu, not from an official source. Bandai Namco's patch notes list no OS Tuning values, and the wikis disagree on one cost (below), so the full-tree total is given as a range of 194 or 197 chips. Anything unconfirmed is flagged.
How many OST Chips you get: 98 in the first run, 99 more from ANALYSIS
You earn OST Chips by beating opponents in the Arena, not from Combat Logs. The Arena and OS Tuning open after you clear the Chapter 1 mission "Retrieve Combat Logs". Chips per opponent (from VGKAMI's list; the 98 total matches the Fextralife wiki's "98 on a first playthrough"):
| Arena ranks | Unlocked after | Chips each | Opponents | Subtotal | Running total |
|---|---|---|---|---|---|
| 29/F to 27/F | Retrieve Combat Logs | 2 | 3 | 6 | 6 |
| 26/E to 23/E | Attack the Watchpoint | 2 | 4 | 8 | 14 |
| 22/D to 18/D | Ocean Crossing | 3 | 5 | 15 | 29 |
| 17/C to 13/C | Tunnel Sabotage | 3 | 5 | 15 | 44 |
| 12/B to 08/B | Attack the Old Spaceport | 4 | 5 | 20 | 64 |
| 07/A to 04/A | Destroy the Ice Worm | 4 | 4 | 16 | 80 |
| 03/S to 01/S | Underground Exploration - Depth 3 | 6 | 3 | 18 | 98 |
Subtotals and running totals are my arithmetic from the per-opponent values. The remaining 99 chips come from the ANALYSIS battles that appear in New Game+: A-1 to A-3 give 8 each (24), B-1 to B-3 give 10 each (30), and Y1 to Y3 give 15 each (45). The NG++ D-1 to D-3 battles are listed as 0. That makes 98 + 99 = 197 chips, the amount said to max out the whole tree. A first playthrough covers about half of it.
What everything costs
I cross-checked the Fextralife wiki against Game8's list. Most costs match. The only mismatch is the final tier of the kinetic, explosive and energy damage lines.
| Group | Entry | Chips per step | Effect (as listed by the sources) |
|---|---|---|---|
| System unlocks | Boost Kick | 1 | Ends an Assault Boost with a damaging kick |
| Quick Turn | 1 | Snap-turn to the side or rear | |
| Weapon Bay | 2 | Mount arm weapons on your shoulders and swap them in | |
| Weight Control | 3 | Sortie while overweight; purge weapons to cut weight | |
| Manual Aiming | 2 | Manual reticle control | |
| Core Expansions | Assault Armor | 1 / 3 / 5 | Pulse blast that cancels incoming fire and damages nearby enemies |
| Pulse Protection | 2 / 3 / 4 | Stationary barrier at a fixed spot | |
| Pulse Armor | 3 / 5 | Barrier that follows the AC | |
| Terminal Armor | 5 | Triggers automatically when AP is drained | |
| Offensive tuning | Kinetic Weapons - Fire Control Tuning | 2 / 3 / 4 / 5 / 6 or 7 | Kinetic damage +3 / 6 / 9 / 12 / 15% |
| Explosive Weapons - Fuse Control Tuning | same | Explosive damage +3 / 6 / 9 / 12 / 15% | |
| Energy Weapons - Output Control Tuning | same | Energy damage +3 / 6 / 9 / 12 / 15% | |
| Melee Weapons - Drive Control Tuning | 3 / 5 / 7 | Melee damage +5 / 10 / 15% | |
| Direct Hit Modifier - Damage Tuning | 4 / 6 / 8 | Damage to staggered enemies +5 / 10 / 15% | |
| Access Speed - Optimization | 2 / 4 | Access (door and terminal interaction) speed +50% / +100% | |
| Defensive tuning | ACS - Dynamic Deflection Control Tuning | 2 / 4 / 6 / 8 / 10 | Damage taken -3 / 6 / 9 / 12 / 15% |
| Repair Kits - Optimization | 3 / 5 / 7 / 10 | Repair Kits restore 500 / 1,000 / 1,500 / 2,000 more AP |
- The disputed cost: the Fextralife wiki lists the last tier of the three damage lines as 7 chips (install 2, then 3 / 4 / 5 / 7); Game8 lists 6 (2 / 3 / 4 / 5 / 6). I could not confirm which one the current game uses.
- Totals: system unlocks 9, Core Expansions 31 and defensive tuning 55 agree on both sites. Offensive tuning is 99 chips if the last tier costs 6, or 102 if it costs 7. The whole tree is therefore 194 or 197 chips. Only the 7-chip case matches the 197 you can earn, but that just fits the claim that everything can be bought; it is not independent proof.
- Reading the percentages: I read the first percentage as applying the moment you install the entry (Game8 and ggrecon list it that way). The Fextralife wiki only lists the upgrades after installing, which is why its numbers look shifted.
- The offensive lines are separate per weapon type, and melee is excluded from the kinetic, explosive and energy lines. Chips in a line you do not use do nothing for you.
- The Japanese-version names for these entries are not cross-checked here; the English names above are the ones used by the sources.
The order to buy in, and a 98-chip example
This order is my own judgment, built on Game8's star ratings and chip efficiency. It is not an official recommendation. Game8 rates Boost Kick, the weapon damage lines, Direct Hit Modifier, melee tuning and ACS at 5 stars, and Repair Kits and Assault Armor at 4.
- Boost Kick (1), Quick Turn (1), Weapon Bay (2) and the Assault Armor unlock (1) = 5 chips. They widen your options cheaply and fit inside the first 6 Arena chips.
- The damage line for your main weapon type, up to the fourth step (2 + 3 + 4 + 5 = 14 chips), for +12%. Running total: 19. The last step (15%) costs 6 to 7 more, so it comes last.
- Direct Hit Modifier, all steps (4 + 6 + 8 = 18). It only applies to hits on a staggered enemy, so it pays off on ACs that build stagger and follow up (up to +15%). Running total: 37.
- ACS damage reduction, all steps (2 + 4 + 6 + 8 + 10 = 30), for 15% less damage taken. Running total: 67.
- Repair Kits, all steps (3 + 5 + 7 + 10 = 25), for +2,000 AP per kit. Running total: 92.
That spends 92 of the first-run 98 chips and leaves 6, enough for the last damage step only if it costs 6, or for extra Assault Armor steps. For a melee AC, swap step 2 for Melee Weapons tuning (3 + 5 + 7 = 15), which brings the total to 93.
Nothing here is locked in. You can respec OS Tuning for a COAM fee; the Fextralife wiki says the fee rises with the chips you hold, and I could not find the amount. Start with the cheap unlocks and swap entries later if they do not suit your AC.
Common questions
- Is Manual Aiming worth it? Not early. Game8 gives it 1 star, and PCGamesN says it gives no benefit unless you play with a mouse and makes the game harder.
- Access Speed? Last. It only speeds up door and terminal interactions (sources word it as either 'less time' or '+% speed').
- Can I run every Core Expansion? No, only one can be equipped at a time, so rushing the extra steps on all four is wasteful.
- Why am I short on chips? That is by design in the first run. Maxing everything needs the 99 chips from ANALYSIS in New Game+.
Limits of this guide
- Numbers are from the Fextralife wiki (edited 2024-12-15), Game8 (updated 2025-11-21), ggrecon, VGKAMI and PCGamesN. I did not measure them in the in-game OS Tuning menu.
- The official notes I could read in full are Version 1.09 (2025-05-23), which contain no OS Tuning or OST Chip entry. I did not read the 1.03 to 1.08.1 notes in full; a search turned up no OS Tuning changes.
- Not confirmed: whether Terminal Armor also heals (sources disagree), the exact top-tier wording for Repair Kits, and the fine conditions for NG+ chip rewards.
- I did not test how much each entry speeds up real fights.
Sources
- Fextralife Wiki: OS Tuning — costs, effects, 98 chips in a first run; edited 2024-12-15
- Game8: OS Tuning list (Japanese) — costs per step and star ratings; updated 2025-11-21
- VGKAMI: How to get OST Chips — Arena and ANALYSIS chip values, 197 total
- ggrecon: OST Chips and upgrades — percentage steps per upgrade
- PCGamesN: All Armored Core 6 OS upgrades — effect descriptions
- ARMORED CORE official: 2026-09-18 update notice — confirms Regulation Ver. 1.09.1 is current
- Bandai Namco: Patch Notes Version 1.09 — confirms no OS Tuning entry
