# Hardware Wallet Showdown: Trezor Patches Microcontroller Flaw After Ledger's Discovery

Here's the tea: Ledger's research team (Donjon) just exposed a nasty vulnerability in Trezor's Safe 3 and 5 models, and it's not your typical firmware issue. The problem sits in the microcontroller itself—a component Trezor relies on as part of its two-chip security architecture.

# # What went wrong?

Trezor had implemented a firmware integrity check to prevent software tampering, but Ledger researchers showed that attackers could actually bypass it. The core issue? Cryptographic operations were being executed directly on the microcontroller, which could theoretically be exploited with advanced physical attacks—think sophisticated hardware hacking, not just voltage glitching.

# # The fix (and what's weird about it)

Trezor confirmed it patched the vulnerability, but here's the kicker: **the company says a firmware update won't work**. Translation? This required hardware-level changes. Trezor recommends buying devices from official sources to avoid supply chain risks, but frustratingly, they're keeping the technical details locked down.

# # The irony

While Trezor was dealing with this, Ledger itself isn't exactly squeaky clean. In December 2023, hackers breached Ledger's connector library and siphoned $484K in crypto. Before that, 270,000 customer mailing addresses got leaked. So the company pointing out vulnerabilities has its own security scars.

# # Why this matters

Charles Guillemet (Ledger's CTO) made a fair point: better security across the ecosystem = more mainstream adoption. But this incident also exposes how hardware wallets operate in a game of constant cat-and-mouse with attackers. The good news? Trezor's Secure Elements (dedicated chips for PIN and crypto keys) still hold up well against low-cost physical attacks. The bad news? Advanced threats remain a reality.

**Bottom line**: Your funds aren't at immediate risk if you own a Trezor Safe 3/5, but this is a reminder—always buy from official channels and stay updated.