The R5F100CF is the 96 KB member of the 36-ball wafer-level row, and it is
where the row crosses the family’s data-flash boundary: from this capacity
upward the separate data array is 8 KB rather than 4 KB. The package stays a
4 by 4 mm body with no leads, the converter stays at eight channels, and the
code array becomes ninety-six one-kilobyte blocks with the boot-swap
machinery that large images use routinely.

Eight KB of data flash changes the evidence picture

Below 96 KB of code flash the data flash is 4 KB; at 96 KB and above it is 8
KB. The doubling turns the data array from a calibration store with a little
room left over into a genuine log, and appliance and metering firmware at
this capacity uses it that way: fault records, session counters, calibration
generations. For a recovery job the array is the unit’s biography, and it is
read with the data-flash command set and captured with its own protection
flags noted, separate from the code-side configuration.

Ninety-six blocks and the swap in daily use

Ninety-six kilobytes is ninety-six erase blocks, and the boot machinery
occupies the familiar bottom slice: four blocks of boot region, four of
mirror, one flag byte choosing between them. Products updated in the
field carry both generations, and the older copy usually still holds the
firmware the unit was born with. A capture walks the whole array in one
pass and takes the diff for free, which is the closest thing to a
changelog the manufacturer never published.

RAM and the library residency

With 8 KB of volatile memory the flash library runs from RAM with room for
the update protocol and the application’s state as well. The self-RAM
reservation in a recovered linker map marks an image built for updates, and
the same window is where a readout loader belongs. In-circuit capture on
this member is comfortable: the sequencer’s idle time serves the read path,
and the verification is per block, so contact problems announce themselves
as localised checksum failures. The loader itself, sized for the space
below the window, streams the whole array in one pass and finishes with
the application none the wiser.

Identifiers under the grid

One ten-byte secret answers the emulator, the other answers the TOOL0
programmer, and the option byte between them decides what a failed debug
comparison costs, up to an erase of everything. Consumer boards at this
capacity nearly always carry the serial secret, because that is the path
the production line programmed through, and the debug side varies with
the authors’ caution. Block zero, read passively, resolves the whole
question.

Access and the bench

The 0.5 mm ball grid takes a fixture where the layout allows clearance, and
the lift-and-reball route onto an adapter is routine when it does not,
returning the part to service afterwards. The single-wire TOOL0 pad on P40
remains the pin worth locating on any layout. When the package is the
obstacle and the image must come from below it, the IC decapsulation service service
reaches the die, and package-level examination is part of the chip reverse engineering service flow.

Row context

The 36-pin siblings are in R5F100CA flash memory through R5F100CE memory readout and the
128 KB R5F100CG flash heximal. The 96 KB die in leaded packages is the 30-pin
R5F100AF memory readout, the 32-pin QFN R5F100BF memory dump and the 40-pin
R5F100EF flash memory. For the protection contrast with a family that kept a single
4 KB data window regardless of capacity, see LPC2134FBD64 mcu flash memory, and the
family-level service index is microcontroller unlock.

Log capacity and the 8 KB era

The doubled data store changes what firmware authors are willing to
record. Fault logs stop being ring buffers of a few dozen entries and
become near-permanent histories; energy counters accumulate per cycle
instead of per day; calibration keeps revisions instead of overwriting.
Reading such an array is therefore less like taking a snapshot and more
like recovering an archive, and ordering matters: the wear-levelling map
itself, usually near the front of the array, tells the reader which
records are current and which are superseded. A dump taken without
understanding that map produces data that looks contradictory and is not.