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A Permanent Fix for OpenAI Codex's Phone Verification Lockout

By 金色的暴发户 ·
Read original on juejin.cn ↗ Google Translate ↗ Alt translation

Codex's phone-binding policy creates a hard lockout for developers in regions it doesn't officially support, and the common workaround of disposable SMS numbers is a trap that destroys accounts on re-verification. A £10 UK SIM with near-zero maintenance cost removes that risk permanently.

Summary

Codex's SMS verification rejects +86 numbers and locks the bound phone number permanently, so losing access to a temporary virtual number means losing the account. SMS verification platforms offer only a short-term fix that collapses the moment a risk-control check triggers a second login. The only durable solution is a real, long-lived foreign mobile number.

A UK giffgaff SIM or eSIM costs £10 to activate and stays alive indefinitely with one 30p text every six months. The carrier does not require real-name registration and accepts Visa payment directly from China. Physical SIMs are available on JD.com under the search term "UK gg envelope," and a modified giffgaff APK bypasses the eSIM hardware check on Chinese Android phones that lack eSIM support.

The eSIM activation code expires in 24 hours, so the workflow requires timing the application with the arrival of a blank programmable SIM card and a card reader from Taobao. Once activated, the number works for Codex and any other service that demands a non-Chinese phone number.

Takeaways
OpenAI Codex no longer accepts +86 Chinese phone numbers for SMS verification and permanently locks the bound number to the account.
Temporary SMS verification platforms fail catastrophically when Codex triggers a second verification step, because the original virtual number is unrecoverable.
A UK giffgaff physical SIM or eSIM costs £10 to activate and requires only one 30p outgoing text every six months to stay alive.
Physical giffgaff SIMs are sold on JD.com under the search term "UK gg envelope"; the official store does not ship to China.
Chinese Android phones without eSIM hardware can apply for a giffgaff eSIM using a modified APK that hardcodes the eSIM support check to true.
The eSIM activation code is valid for only 24 hours, so the application must be timed with the arrival of a blank programmable SIM card and a USB card reader.
Turning off international roaming immediately after activation prevents the £10 balance from draining in minutes.
Sending a text message to the giffgaff number itself is the most reliable way to trigger the keep-alive activity from China.
Conclusions

Codex's phone-binding design is unusually brittle: it locks a number permanently with no recovery path, which turns a routine SMS verification step into a single point of account failure.

The giffgaff workaround is not a hack but a legitimate carrier relationship, which makes it more durable than any VPN or virtual-number service that platforms can blacklist.

The modified APK approach to bypassing eSIM hardware checks is a practical reminder that many regional restrictions are enforced client-side and can be circumvented with a simple boolean change.

The 24-hour activation window combined with physical hardware delivery creates a fragile timing dependency that could easily burn a £10 top-up if the card reader arrives late.

Concepts & terms
giffgaff
A UK-based mobile virtual network operator (MVNO) running on the O2 network. It offers pay-as-you-go SIMs with no contract and no monthly fee, making it popular for long-term number holding with minimal cost.
eSIM
An embedded SIM standard that replaces a physical SIM card with a programmable chip soldered into the device. Activation uses a downloadable profile rather than a physical card swap.
SMS verification platform
A service that provides temporary, disposable phone numbers for receiving SMS verification codes. Numbers are typically shared or recycled, making them unreliable for accounts that require re-verification.
Source: juejin.cn ↗ Google Translate ↗ Backup ↗