# Zkool - The successor to Ywallet

**URL:** <https://forum.zcashcommunity.com/t/zkool-the-successor-to-ywallet/51139>\
**Category:** Zcash Apps\
**Created:** [May 1, 2025, 8:50am UTC](https://forum.zcashcommunity.com/t/zkool-the-successor-to-ywallet/51139 "2025-05-01T08:50:36Z")\
**Posts on this page:** 1\
**Showing post:** 45

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**Author:** ![andrey.lorer](https://avatars.discourse-cdn.com/v4/letter/a/48db29/32.png) [@andrey.lorer](https://forum.zcashcommunity.com/u/andrey.lorer)\
**Post date:** [May 5, 2026, 3:30pm UTC](https://forum.zcashcommunity.com/t/zkool-the-successor-to-ywallet/51139/45 "2026-05-05T15:30:55Z")

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Hi hanh,

I’m reaching out because you’re one of the few people who deeply understands both Zcash protocol internals and Ledger integration.

**My situation:**

- **Device:** Original Ledger Nano S (functional, PIN known)

- **Amount:** 100 ZEC (~€40,000)

- **Address:** t1ZsfDa4kpk8aYjffUgv149suF2i54hLH4P

- **Transaction date:** May 25, 2018 — one month BEFORE Overwinter activation (block 347500)

- **Problem:** Pre-Overwinter UTXOs (v1 transaction format)

- **Critical issue:** I lost my 24-word recovery phrase

**What I’ve tried:**

1. Ledger Live + standard Zcash app → `bad-tx-consensus-branch-id-mismatch`

2. Zondax ZecWallet + Zcash Shielded app → syncs but doesn’t find 2018 UTXOs

3. Contacted Zondax → they confirmed no solution for pre-Overwinter format

4. Contacted Ledger support → they confirmed Zkool solution requires Nano S Plus (Zcash Shielded app on Nano S doesn’t support NU6)

**The core problem:**

- Zkool + Zcash Shielded can recover old UTXOs (v1, v2, v3), but only on Nano S Plus/X/Stax

- Original Nano S has old Zcash Shielded version that doesn’t support NU6

- Without seed, I can’t migrate to a newer device

- The private key is locked inside the Secure Element

**My question:**

Is there ANY technical path to spend pre-Overwinter transparent UTXOs from an original Ledger Nano S without the seed phrase?

I’m thinking:

- Modified Ledger app that supports v1 transaction signing on Nano S?

- Some way to use the old Zcash app (not Shielded) with correct branch ID?

- Any other approach I haven’t considered?

**I am willing to fund development** of a solution — up to €40,000 (the value of the locked funds). If you’re interested or know someone who could help, please let me know.

Thank you for your time.

Best regards, Andrey

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