[Android Q&A, Help & Troubleshooting] TheDrive:
1. Thanks for the sources. Casio closed original site and sources too.

I do attach all the files they published. It seems to be a small piece of all the sources they hide.

View attachment 4128870

2. I do rarely visit this topic. I do NOT have this device nor ever had nor even ever seen it live. You can find me via PM here or in the Russian 4pda.ru forums.

It's a good idea to write to this topic, but you should some kind aknowledge me to read. I've now subscribed to this thread and will try to visit if someone is looking for me.

3. I never compiled AOSP for any device. I do afraid and wanna escape when I see instructions I should get 10GB of sources, setup 1GB compilation environment and compile for 2-3 hours on the multicore PC. :)

I've explored your binaries .

I've no working Casio FW's by my hand now to compare

I don't know what is bootloader (w/o extension). Secondary booloader - SBL on these Casio phones as far as I can remember consists of the files SBL1/SBL2/SBL2/RPM/TZ. 3rd bootoader is aboot - it seems to be bootloader is identical to emmc_appsboot.mbn and EMMCBOOT.MBN so it should be the aboot image.

Aboot should provide fastboot finctionality, useful to flash FW, so I wouldn't touch (reflash) it w/o a reason.

Kernel should be the kernel built into the boot.img It useless for flashing.

Same about ramdisk.img

Same about recovery-ramdisk.img but this package should be built into the recovery.img not the boot.img. boot.img is a Linux kernel with a RAM disk ready to flash. boot.img seems to be correct, but I don't know will it work or hang.

system.img and userdata.img should be ext4 images of the system and data (userdata) partitions. I don't know are they full of required files or not.

Compare contents (unpack ExtFS images compare file lists and contents) with and original firmare images.

cache.img and persist.img seems to be empty ext4 images. I can't remember should factory persist image contain any data or not. Do compare.

You can find a variety of the factory and custom FW's in the 4pda.ru topic I've linked in the above messages. There are instructions there how to flash custom FW's too. That topic seems to be the place this device(s) most discussed in the world ever (over 250 pages). However this device was never officially sold in Russia at all. Idiot's in Casion/Nec failed to enter the most perspective market.

Russians (and CIS) ordered these devices from the USA (locked ones!) and other countries including used ones for an expensive prices. Our country is full of the wild nature places free for visiting and trip (unless you wouldn't do a something scary to the nature). That's why these phones, ready to fall-and-wet, are so required here, espacially by the professional and amateur fishers and hunters and simply trippers.

To flash use standard procedures, I don't know which mode is the best to use.

Images should be ready to flash in the standard fastboot mode. To use official upgrade method there was some util which flashed official FW's assembled into the one-big-file container. One user from AndroidForums have developed util to unpack them. I don't think you should write your util to repack it back. :)

To be on the safe side you should have all the backups, including full flash image and the particular partition images of the every partition.

In common people most probably custom some parts of the system image. More rarely the kernel (boot.img) and yet more rarely anything else.

It seems userdata partition contains 133MB of the initial data. In many devices userdata could be freely erased and formatted to make device 'factory new' in the FW part. This one contains something of amount. Probably some bundled applications and their data.

You can discuss also in some AOSP/other FW customization topics related to the recompilation of the sources. There should be more people there able to advice you with a source related aspects.

Sorry for an errors and mistyping, if any, no time to check and correct.