R5F100FH is the 192 KB member of the 44-pin LQFP row: 16 KB of RAM, the 8 KB
data flash, ten converter channels and forty I/O in the 10 by 10 mm body at
0.8 mm pitch. It is the capacity at which the family’s largest images appear
on serviceable leaded packages, and the point where segmented addressing,
the boot-swap update zone and a substantial data array all operate in a
package the bench can work with freely.

One hundred ninety-two blocks of segmented code

The code array divides into one hundred ninety-two one-kilobyte blocks with
the boot cluster in the first four and the swap target at 02000H. Above the
flash the image is segmented: the core addresses its megabyte through
segment registers and far pointers, and at this capacity the compiler uses
them without restraint. Any reconstruction carries segment context through
the whole image or the result does not run, which is the central technical
discipline of work at this member and its neighbours.

Sixteen KB of RAM as the working set

Sixteen kilobytes let the image carry the flash library, an updater,
communication buffers and the application’s own working set at once,
and the library’s reservation at the top of the space flags an
update-capable build. Both boot copies are written on boards of this
class, the first block carries the byte that names the live one, and
the retired copy keeps the generation the product shipped with. Read
together, the two copies explain every update the unit ever received.

The 8 KB data flash and the service record

The separate data array is the 8 KB version here, holding fault histories,
calibration generations and usage logs under wear levelling. It is read
with the data-flash command set, protected by its own flags, and it dates
the unit’s service life in a form that survives disputes. On industrial
boards of this class the array is frequently the only surviving record of
how the unit was used and modified.

Protection and the passive first read

The whole security posture sits in the first kilobyte: the four option
bytes with their watchdog, detector and oscillator policies, the debug
gate and its wipe-on-failure choice in the fourth, and the two ten-byte
identifiers that gate the emulator and the serial programmer
independently. The serial one is nearly always present on boards of
this size, which says the production programmer path was the intended
one. A passive read of the block, before any tool attaches, fixes the
plan; the shield window, where present, is noted with the same
capture.

Access and the bench

The package forgives everything: fixtures, adapters, lifts, and a
reflow that returns the part to its board. The IC decapsulation service route
covers the rare silicon-level job, the firmware extraction service page covers the
streaming workflow, and project-level handling is the chip reverse engineering service flow.

Row context

The 44-pin siblings are in R5F100FA memory readout through R5F100FG memory dump and
R5F100FJ flash memory to R5F100FL firmware decryption. The same capacity in other packages is
the 40-pin R5F100EH firmware decryption and the 48-pin R5F100GH flash data. For the boot-swap
mechanics in detail, see R5F100FE boot cluster recovery, and the family service entry
is the MCU crack service page.

Module versioning visible in the array

A 192 KB image is large enough that its authors keep versioned
modules, and the evidence survives in the capture: repeated structures
with different revision stamps, string tables that grow across
generations, driver code that persists unchanged while the
application around it is patched. Comparing the live boot copy with
its inactive twin surfaces the manufacturer’s actual change history,
which is often the missing context in a support dispute. The
doubled data store carries the corresponding run history, and the
three together, code, mirror and log, let a rebuilt unit resume the
specific board’s life rather than a generic one.

The diff discipline is simple and strict: compare the boot copies block by block, record which blocks differ, and map the differences onto the module boundaries the version stamps suggest. The result is a change history the manufacturer’s own release notes rarely match, because it reflects what shipped rather than what was planned. On a 192 KB image the diff is small work with disproportionate value, and it reuses data the capture already holds.