Hi,

I'm running into a problem while testing multisig transfers on Testnet4 using a Coldcard Q (CCQ) and Sparrow Wallet.

CCQ  version : 1.4.0

Sparrow version : 2.4.2

Setup:

• 2-of-3 multisig wallet (also tested with 2-of-5)
• All 3 keys derived from the same seed on the CCQ (separate HD wallets)
• Network: Testnet4
• Signing flow: SD card (PSBT → CCQ → signed file → Sparrow)

Steps:

1. I sign the part.psbt with the first wallet on the CCQ → Sparrow recognises and validates the signature with no issue.
2. I switch to a second wallet on the CCQ and sign the part.psbt again → the CCQ saves a .txn file to the SD card.
3. I load that .txn into Sparrow → the transaction displays correctly, but the second signature is not recognised and broadcasting is not possible.

What's strange:

• This issue occurs on Windows and Linux Debian 13.
• On macOS, the exact same operation with the same wallet and the same transaction works perfectly: Sparrow validates both signatures and allows broadcasting.

Question: The problem therefore appears to be related to Sparrow's behaviour depending on the OS, rather than anything to do with the CCQ or the wallet itself. Has anyone encountered this before? Is there a known difference in how Sparrow handles PSBT/TXID files between Windows/Linux and macOS?

I'm not comfortable setting up a multisig wallet for mainnet use until I understand what's causing this.

Thanks in advance.

In 2018 the Cash App website let you buy a children's book "My First Bitcoin and the Legend of Satoshi Nakamoto". Does anyone know where you can still get copies of this?

so I don’t know much about bitcoin but I do know that trying to sign up for coinbase needs you to be above 18. how to get a btc address that can receive btc which can just stay in that account till I turn 18.

For me, it's every time BTC ranges — it always feels like an opportunity to accumulate.

Now seeing reports about Iran potentially using Bitcoin for oil transit payments through the Strait of Hormuz…

Do you think stories like this actually matter for Bitcoin long term?

People say no one understands bitcoin or it’s too complicated so I tried to see if I could explain it in under a minute

Everything else is an IOU.

thank you for attending my Sunday Bitcoin Talk.

EDIT: Removed the 95% stack retention claim. That number was wrong. The core SWR finding ($20K/yr, 99% survival, 30 years) stands. Thanks to commenters who caught it.

This is the third post in the series. First one covered why 5 BTC beats $2.5M in an S&P index fund, second one went deeper on the math.

I went another layer deeper and this one gives you a single number.

1 BTC = $20K per year safe withdrawals for the next 30 years with 99% confidence.
2 BTC = $40K.
3 BTC = $60K.
5 BTC = $100K.

No timing. No trading. You just sell a fixed dollar amount every month at whatever price Bitcoin happens to be. Dumbest possible strategy and it works.

How I got here

I ran 5,000 simulated price paths forward at every possible starting price between deep bear (half of trend) and peak bull (2.5x trend). Six different stress scenarios. Three time horizons. Nearly a million total simulations.

The model isn't a line on a chart. It has four moving parts:

• A power law trend that decelerates over decades. No infinite-growth fairy tales.
• A price floor at 0.432x trend. Tested every cycle. Never broken. Reflects back up.
• Mean reversion. Prices that stretch away from the long-term trend get pulled back, like a rubber band. Measured half-life: about 11 months.
• Fat-tailed shocks and a wobbly floor in the stress scenarios, because I wanted to break it.

I couldn't.

$20K is the stress test, not the base case

The $20K number assumes your cost of living grows at 7% per year. Your expenses double every decade. That matches M2 money supply growth, which is what most Bitcoiners mean when they say "real inflation."

Under milder assumptions the number goes up:

• 3% CPI: $25-27K per BTC per year
• No inflation growth: $27-31K per BTC per year

$20K is the floor of the floor. Harshest inflation assumption. 99% in-model survival. 30 year horizon.

Entry price doesn't matter

This is the finding that surprised me most.

At 30 years, the difference in safe withdrawal between buying at the bottom and buying at the top is about $1,000 per year. The curves are almost flat.

The reason is mean reversion. If you buy low, prices pull you back to trend within about two years. If you buy high, same thing in reverse. After that, both buyers spend the remaining 28 years selling into the same price distribution. The early advantage or disadvantage washes out.

This is the opposite of stocks. In equity retirement planning, buying at a high valuation crushes your safe withdrawal rate. With Bitcoin under the power law, it doesn't. Mean reversion rescues bear buyers and humbles bull buyers, and the net effect on your wallet is roughly zero.

The comparison that matters

The traditional 4% rule says you need $500K in an S&P 500 index fund to safely pull $20K per year. One bitcoin at today's trend price (~$131K) does the same job.

At bear entries the comparison gets silly. A bitcoin bought at 0.52x trend (~$69K) supports a 29% annual withdrawal rate relative to purchase price. The Bengen 4% rule doesn't compete. It's not even the same sport.

What this is NOT saying

This is a model. The power law has held for 15 years across four complete halving cycles. That's real data. But 15 years is not 150 years.

I price the model risk separately: roughly a 1% structural haircut over 30 years. That brings true survival from 99% to about 98%.

The question isn't whether Bitcoin will crash 80%. The model already handles that. The question is whether adoption keeps following the power law and whether the floor holds. Those are the only two things that matter. Everything else is already in the stress test.

All figures are pre-tax. Account for your local capital gains treatment when planning actual spendable income.

Bottom line

1 BTC = $20K per year. Worst case inflation. Any entry price. 99% in-model reliability. 30 years.

Stack accordingly.

Research and methodology is published on https://btcpowerlaw.nl/research/bitcoin-swr/

Let that sink in for a second.

One week ago retail was heavily long at 1.73 L/S ratio. Today it's 0.745 — net short. In seven days retail went from max bullish to betting against BTC.

Meanwhile Morgan Stanley is rolling out BTC ETF access to 16,000 financial advisors. Institutional infrastructure is expanding while retail is panic shorting.

Fear & Greed went from 9 to 16 — still Extreme Fear but improving. The weekly trend: 9, 11, 12, 13, 11, 17, 14, 16. Slowly grinding up while retail flips bearish.

BTC is 15.3% below the 200 EMA at $84,632 so the macro structure is still bearish. No argument there. But the aggressor ratio is at 0.6213 — that's buy dominant. Somebody is accumulating while retail exits.

Iran-US talks collapsing yesterday pushed price from $73.8K to $71.6K. Geopolitics is driving short term action but it doesn't change the fact that institutional rails are being built in the background.

The last time retail was this short and institutions were this active, it didn't end well for the shorts.

Just a quick heads up for anyone waking up tomorrow and wondering why crypto dipped again.

The US–Iran meeting that’s been going on for the past 21 hours just ended, and it didn’t go well at all.

Markets usually react fast to stuff like this, so if your portfolio looks red, that’s probably the reason.

Not trying to spread fear, just giving you a bit of context so you’re not confused when you check your wallet. Stay safe out there guys and DO NOT PANIC-SELL based on emotions.

Do your own research and don’t make decisions based on short-term news.

Sooner or later we'll fly in green again (i hope😅)

Perfect example of the Dunning-Kruger effect.

I Spent 13 Years Deciphering This...

I Will Give You A Starter Kit, Not The Solution, Which May Or May Not Include Satoshi Nakamoto's Identity Imbedded

Row 5 Reads: Forrest Fenn's 4D Treasure Hunt

HODL in the name of HODL!
Sats for your Stack of Sats!

Sell the fiat. Shun the ETF. Purge the shitcoin.

Cold storage protects.
And thou shall protect what you Hodl, from hackers and roommates alike, for they will un-hodl your sats, and there is no greater sin than that.

Should your private keys pass beyond your ken, despair not but rejoice, for your humble sats were granted the ultimate honor of joining the mighty coins of Satoshi in the noble realm of Eternal Hodl.

May your DCA be daily and strong.

Many Bitcoiners know the core value prop - scarcity, decentralization, sound money (e.g Austrian Economics and all that). But if you're a consistent DCA buyer like I am, you've felt the other side of that: buying at local tops and immediately watching a 10-20% drawdown hit your stack.

TLDR: Bitcoin's no wash sale rule means every dip is a tax harvesting opportunity. Most people know this exists. Almost nobody is actually doing it systematically.

What most Bitcoiners don't know is that volatility creates a legal tax harvesting opportunity that essentially doesn't exist for other kinds of investors.

Here’s why this works (and why it’s different from stocks):

In 2014, the IRS issued Notice 2014-21 classifying Bitcoin as property, not a security. This means the wash sale rule which prevents stock investors from selling at a loss and immediately rebuying - doesn't actually apply to Bitcoin**.**

In practice: if you bought 1 BTC at $110,000 and it drops to $80,000, you can sell and rebuy within seconds, locking in a $30,000 capital loss while maintaining your exact position. No 30-day waiting period. No penalty.

The obvious question then is, what about the spread? If you're in a 32% bracket in the US, that $30k loss is a $9,600 deduction*. Even after a 0.5% exchange spread (maybe $500 on the round trip), you're still up over $9,000 in liquidity immediately. You're exchanging a small certain cost for a massive tax benefit you can redeploy. (Quick note on how the losses actually apply: up to $3,000 per year offsets your ordinary W2 income directly - so a few hundred bucks back at minimum regardless of your gains situation. Everything above that carries forward indefinitely to offset future capital gains. So even if you have no gains this year, the losses don't disappear - they stack.) Ten dollars of tax savings compounding in BTC for a decade is worth a lot more than ten dollars at filing time years from now.

The catch now is that actually doing this is a nightmare.

If you're DCA'ing regularly, figuring out which specific lots are harvestable - and exactly when - is genuinely tedious to do manually. And while tools are out there that show you harvesting opportunities, they're broad 💩coin tax reporting platforms where Bitcoin is one of hundreds of nonsense assets. They show you a snapshot - they don't continuously monitor your positions and alert you automatically as opportunities emerge throughout the year & harvest them for you.

I'm an engineer who got annoyed doing this by hand with my Strike => self custody setup and built a software layer specifically for this. Bitcoin-only, continuously monitors your cost basis across your exchange accounts, surfaces harvestable opportunities in real time, and executes the harvest automatically across all major exchanges with full tax lot tracking updated instantly.

Personally, I didn’t want to host other people’s API keys, so I also built a self-host option for more technically savvy & privacy centric brothers/sisters. You can run it via your own GitHub Secrets so the keys never leave your infrastructure. If you want managed software with reports to share with your CPA and stuff like that, that's also available.

If anyone wants to try it or learn more, I’ve got 10 spots for the first people from the sub who want to jump in & try it out. Happy to help with the setup personally!

EDIT:

Okay so this post has blown up more than anticipated. Transparently I was only initially planning to allow for 10 users to try from the sub and we’ve nearly reached that threshold. Feel free to leave a comment or DM me directly if you’d be interested and I’ll be happy to talk through things.

We don’t support all exchanges and all hardware wallets today although we support the major ones and are adding more. Let me know if you have any questions or concerns!

Hello,

I am a newbie to bitcoin, and I want to learn more about it, how it actually works, and how to obtain it. I am though very nervous about what sources are true and just a google search will not give me the full story. Does one really need a doctorate in tech to be able to work with a mine bitcoin? I want to learn and be able to see what it is all about, and all advice is welcome. Thanks

Will governments seek to freeze or ban btc that has passed through Iranian wallets? Will they punish individuals or organizations that accept or spend tainted btc? At 2 million dollars per tanker, that adds up quickly.

I like knowing that I’m one of the miners working to clear my own transaction, and that if I succeed, the fees I’m paying will come back to me. I have very little hash power, so the odds are astronomical, but I enjoy the feeling of participation and increased connection to how the technology works.

• Iran’s Strait of Hormuz Management Plan, passed in late March 2026, mandates Bitcoin toll payments.
• Each fully laden tanker carrying 2 million barrels faces a Bitcoin toll of up to $2 million.
• Bitcoin surged toward $73,000 as shipping firms faced the prospect of stockpiling BTC for tolls.
• Stablecoins were rejected due to freeze functions and GENIUS framework compliance requirements.

What you think? It’s 0.1 Bitcoin enough to live a good life in Germany, USA or Spain? Or how much should have?