Teams that duplicate encrypted STM32F413RGT6 code assume a single protection switch governs the job. On this 100 MHz Cortex-M4 the option bytes expose two independent mechanisms: global readout protection and per-sector write-protection bits. Reading an image does not mean a fresh 1 MB (G) device will accept it, nor does programming mean the original can be inspected. The concrete problem is producing a byte-identical copy and proving it, without altering the source program, when the two locks can sit in four different combined states.

Two option-byte locks, not one global switch

Readout protection and sector write protection share an option-byte area but act on different things. RDP gates whether the Flash array and debug path can be read at all. The nWRP bits apply per sector, so part of the 1 MB (G) array can be frozen while the rest stays writable, and the 320 KB SRAM is unaffected by either. Clearing one leaves the other exactly as it was.

A target can be open for reading yet closed for writing, a state no single protected label describes. Why lowering RDP from Level 1 first mass-erases the array covers the read side; the write side needs its own treatment. The 64-pin LQFP (R/T) part carries 10 UART, 3 CAN, SAI, DFSDM, Quad-SPI, SDIO and USB OTG FS, so the option bytes must survive a busy peripheral set.

Read permission is not write permission

The practical goal is to duplicate STM32F413RGT6 code once and prove it byte for byte. Consider the sequence: read the original, program a blank device, then read it back to compare. RDP decides step one. nWRP decides the last step, because a write-protected sector rejects erase and program commands even though its contents are readable. An engineer who only checks the read discovers the failure after the blank parts arrive.

The reverse state is just as awkward. If RDP is active but nWRP is clear, you can write a fresh part yet cannot read the original back for comparison, so verification stalls. That is the exact sense in which the two locks are orthogonal. What the ROM bootloader actually permits under protection shows how even the built-in loader respects the split rather than collapsing it into one flag.

To duplicate encrypted STM32F413RGT6 code, read the four-state matrix

The four combinations below are the whole decision space. Each row states what the source allows and what a blank target accepts before any erase command.

Verifying the copy without touching the source image

The brief is explicit: the duplicate must be provable without modifying the original binary. That rules out lowering RDP as a first step, because that transition is destructive on STM32 parts. Verification instead leans on read-back checksums over the delivered file against a digest of the source. How Quad-SPI XIP maps main code off chip is a reminder that the digest must cover every occupied region.

Write-protected sectors on the target must be cleared before programming, and that clearing is a separate option-byte transaction from any readout change. Record each sector’s nWRP state so the final configuration matches the original. Skipping this step produces a copy that boots but cannot be field-updated, a failure a quick bench test will not catch.

Failure modes, decision criteria and workflow

Three errors recur. Treating the 48 to 144 pin options in this line as interchangeable leads to a wrong package assumption for the blank part. Assuming nWRP is global rather than per-sector leaves a half-locked target. Conflating can read with can write wastes a batch of devices. Protective flash behaviour on a different MCU family shows how the same vocabulary hides different rules.

A defensible workflow reads the source digest first, classifies the four-state combination, clears only the needed nWRP bits, programs, then compares the full 1 MB (G) read-back. A locked microcontroller readout-protection case is useful for read-side discipline. When people duplicate STM32F413RGT6 MCU readout protection they are negotiating these two locks; to recover STM32F413RGT6 flash memory and still show a clean comparison, the matrix has to be resolved first. That is the bar a duplicate encrypted STM32F413RGT6 extraction service should be judged against.

To duplicate encrypted STM32F413RGT6 code correctly, treat RDP and nWRP as two independent locks, classify which of the four states you are in, and verify the copy with a sector-by-sector read-back. The source image should never be modified to prove the duplicate; the sector map makes that proof possible. If you need that comparison run on real silicon, our lab can perform it on the supplied devices.

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