fx-Remote Maintenance BETA
Mainly
fx-Remote-Maintenance should provide for fx-Backup/Recovery. For the
GII-calculators there are no OS Updaters available yet (June 2010), which allow
to repair a damaged OS. fx-Remote-Maintenance cannot modify (hack or patch) an OS image!
The
program requires the CESG502 driver. The driver is installed together with FA-124.
WINDOWS
64bit is not supported by CASIO. Workaround: VM.
Win7
32bit needs FA-124 v1.02+.
Possible reasons for a recovery
OS
corruption
It has
been reported, that after an accidently applied fx-OS updater (designed for a
different calculator type), a GII came up with the
primary emergency OS update. This has been due to the four byte invalidation, any fx-OS updater applies, when detecting
problems during the update.
Using
flash-erasing or –writing code lightheadedly can damage the OS, too.
Main
memory corruption
It has
been reported, that after running a certain G1A or provoking a crash with a
certain PRGM-bug, the calculator does not come up again. Most probably this has
been a main memory corruption. As main memory resides in RAM, it is possible,
that this area can be corrupted by a G1A going berserk in the RAM. Under normal
circumstances the main memory is recovered from the autobackup in the flash.
But if the calculator can perform a normal shutdown the corruption is backed up,
too, and the calculator possibly cannot startup any more.
Storage
memory corruption
It could
be possible, f. i. after an interrupted storage memory optimization,
the calculator wouldn’t start up any more. Usually the OS detects such a
situation and resets the storage memory automatically, but it seems possible,
that if the OS tries to build up the main menu, which includes scanning the
storage memory for G1As, the OS hangs. This cannot be mended by an OS recovery.
A special binary has to be uploaded, to reset the storage memory. That would
mean erasure of sectors 0x80270000 to 0x803F0000.
Some References
related to this:
http://www.casiokingdom.org/modules.php?name=Forums&file=viewtopic&p=14338#14338
http://www.casiocalc.org/?showtopic=4868
http://www.casiokingdom.org/modules.php?name=Forums&file=viewtopic&p=14059#14059
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It is
very important to make sure that a valid backup is available before starting
any recovery. If the recovery process does not detect any incompatibilities, it
will erase the OS immediately. The calculator will enter coma, until a valid OS
image is reloaded.
The
toolkit consists of a PC-program pfxRecover.exe (remote-controller) and the
SH3-binary OSRecover.SH3.
OSRecover.SH3
is not a hacked “UpdateExe.BIN”.
OSRecover.SH3 follows a completely different scheme and is programmed from
scratch. It has been assembled and linked with the standard tools (assembler,
linker) included in the CASIO fx-9860-SDK.
The
toolkit has been tested on two fx-9860G, two fx-9860G SD, two
fx-9860 slim, an fx-9860GII SD and an fx-9750GII. Disconnecting during
erasure and flash writing has been performed several times without any harm, t.
i. after restart the process succeeded.
Standard
procedure:
Connect
the calculator via USB.
If the
the OS is still operable, start LINK/Receive (the recovery process will enter
the primary OS updater automatically).
If the
OS is corrupt, the primary OS updater should come up automatically, when the
calculator is switched on.
If even
this does not happen any more, start the primary OS updater by resetting the
calculator with the P-button while having P104 closed or as P104 is not easily
reachable with a GII (9860 as well as 9750), trigger the primary emergency OS
update on the GII-types by simultaneously holding down F2, 4 and AC/ON and
pressing the RESTART-button (the calc should show a blank display after
releasing the keys) and finally pressing 9 and x consecutively.
Start
pfxRecover.exe.
The
first thing one should make is a backup of the calculator’s flash (if still
possible).
The
button “Backup” starts a backup of the memory range 0x80000000 to 0x8026FFFF of
the connected calculator.
The
button “Recover” starts a recovery of the memory range 0x80010000 to 0x8026FFFF
of the connected calculator. The image loaded must have the same calculator ID
as the connected calculator. Before the recovery process enters the
erase-phase, the remote-controller asks for a confirmation.
If the recovering process should go out of sync or if the process is
interrupted by disconnecting the calculator, restart the process.
It is
possible, that OSRecover.SH3 cannot start the primary OS updater automatically
from out of the OS (f. i. on a slim with OS
Security considerations
The only
real danger would be writing or erasing the flash below the address 0x80010000.
Therefore the central flash write- and erase-routines, which are used in
OSRecover.SH3, block out such addresses.
If the
calculator’s BIOS is not known to OSRecover.SH3, it
will show a message and freeze, waiting for the P/RESTART button to be pressed.
The
checksum of the image, which should be recovered is checked by the tool. The
process is cancelled, if the checksum is not correct.