STEINS;GATE RE:BOOT Email Answers & Phone Trigger Choices
Look up STEINS;GATE RE:BOOT email answers by chapter, sender, subject, and reply. Flags, achievements, collectibles, and optional mail are tagged.
Use this as a lookup table. Ctrl+F the subject. Type tells you whether the reply is a true-ending flag, an achievement, a collectible, or optional flavor.
Achievement Kurisu mail and true-ending Kurisu mail in Chapter 4 are different. Save if you want both.
Critical chains at a glance
Most mail can be cleaned up later. These four places are where one reply can force a longer reload or change an ending path:
| Goal | Chapter | Subject | Decision | Why save first |
|---|---|---|---|---|
| True Flag 1 vs achievement | 4 | Did you write it? | Scientist chain for Flag 1; Report → Cup noodles for Discontinuous Qualia | They are different branches from the same starting mail. One run cannot treat them as the same chain. |
| Two Mayuri achievements | 5 | What made me happy today | cosplay vs Fubuki-chan and Kaede-chan | Take one, read its follow-up, reload, then take the other. |
| True Flag 3 vs Froggy collectibles | 7 | The key (ﾉД `) | Security → Reality for Flag 3; Frog / Home branches for collectibles | The same mail feeds multiple goals, so a clean Chapter 7 save prevents a much longer replay. |
| Kurisu vs True ending | 10 | Where are you now? | Ignore for Kurisu; reply Where you are for Flag 6 / True | This is the final ending split. Take Kurisu first, then reload for True. |
If your only goal is the True Ending, prioritize the six Kurisu flag rows marked True Ending Flag below and make sure you read the confirmation mail after each chain. If you are doing 100%, use the walkthrough save-slot plan so achievements and collectibles do not overwrite the route you still need.
| Chapter | Sender | Subject | Reply | Result | Type |
|---|---|---|---|---|---|
| 1 | Mayuri | Upa… | Upa. then Kakeru-kun | Resonant Reaction; RaiNet batch 1; RaiNet’s Mascot | Achievement + Collectible |
| 1 | Faris | The decisive battle is close at hand nya | Red Southern Cross | Princesses of Chaos progress | Collectible |
| 2 | Lukako | I made sweets. | Family → My sister | Cruel Sister (needs Mayuri call 8/01 14:29) | Achievement |
| 3 | Lukako | About Frogs | Gero Froggies | Frog wallpaper batch 1 | Collectible |
| 3 | Faris | PHANTASM is the cat’s meow | Theme Song → RaiNet Kakeru | RaiNet Ep. 13 attachments | Collectible |
| 4 | Suzuha | Akihabara’s | peaceful | Warrior Girl’s Pride | Achievement |
| 4 | Kurisu | Did you write it? | Report → Cup noodles | Discontinuous Qualia | Achievement |
| 4 | Kurisu | Did you write it? | Scientist → … → Why am I still here? | Flag 1; Genius Girl’s Melancholy | True Ending Flag |
| 4 | Faris | Sign of increasing misfortune | He → NyanNyanian | Cat’s Tea Time | Achievement |
| 4 | Faris | Sign of increasing misfortune | He → Chinchilla Start → Ep 8 | RaiNet final batch; Hero of RaiNet | Collectible |
| 4 | Mayuri | Speaking of lotteries | Magazine → Crunchy-kun → Kakeru-kun | RaiNet mid batch | Collectible |
| 4 | Lukako | About RaiNet | (open attachment) | RaiNet summaries | Collectible |
| 5 | Mayuri | What made me happy today | cosplay | Passions Best Forgotten | Achievement |
| 5 | Mayuri | What made me happy today | Fubuki-chan and Kaede-chan | Princesses of Chaos | Achievement |
| 5 | Kurisu | Plans | Traveling expenses | Flag 2 after follow-up mails | True Ending Flag |
| 7 | Kurisu | The key (ﾉД )</td><td>I don't have a key → Security → Reality</td><td>Flag 3</td><td>True Ending Flag</td></tr><tr><td>7</td><td>Kurisu</td><td>The key (ﾉД ) | I don’t have a key → Frog | Frog batch 2 | Collectible |
| 7 | Kurisu | The key (ﾉД `) | Home → Hyahha → I’m gonna give it to you straight | Frog batch 3; Froggy Fad Demise | Collectible |
| 8 | Kurisu | Explain yourself! | (only reply) | Flag 4 after From an unpopular girl | True Ending Flag |
| 9 | Kurisu | Contact me, idiot! | Worried | Flag 5 | True Ending Flag |
| 10 | Kurisu | Where are you now? | Ignore / or Where you are | Kurisu ending vs Flag 6 | True Ending Flag |
You cannot cancel a selected reply in RE:BOOT. Save first. Inbound mail is easier to miss than in the original (KKB). Full chapter context: Walkthrough. Flag write-up: True Ending.
Verification after the September 7 update
The official September 7, 2026 Steam update fixes audio not playing on Steam Deck and notes continued Steam Machine compatibility work. It does not announce changes to Phone Trigger reply behavior, the six True Ending email chains, or achievement/collectible mail requirements. On September 15, the high-risk mail branches above were rechecked against the current Kiri Kiri Basara 100% guide instead of leaving the page at its August 21 launch-week verification date.
Last verified: September 15, 2026. Steam app 4012810. Uncertain items are marked not yet confirmed.
Sources
- Kiri Kiri Basara 100% Guide (Martin, 19 Aug 2026)
- Kiri Kiri Basara review (13 Aug 2026)
- Kiri Kiri Basara Digital Deluxe review (15 Aug 2026)
- Official English site
- Steam store
- Steam achievements
- Steam Community — September 7 update
- Videos used as research (facts extracted, not copied): KKB 100% Guide, KKB review, Noisy Pixel review
STEINSGATEREBOOT.site is an unofficial fan-made guide and is not affiliated with MAGES., Spike Chunsoft, or the game’s rights holders.