NEC MP900C to 900? finally works!!

well, yes, you read right, 900C to 900 and not the other way around
(900 = 900 with HPC2000, 900C = 900 with CE.NET)

the upgrade is no longer one way. it is now technically easily possible to flash any OS onto a nec 900 or 900c, whether hpc2000 or ce.net. linux later as well?

details later still working on polishing the method. all i can say now is bsaunder has been able to flash his 900 to cenet then back to hpc2000 just fine.

my only problem is that this always requires a bootloader reflash as well but it works at least! so, you need to flash hpc2000 bootloader to be able to launch the hpc2000 OS.

would love to be able to launch hpc2000 with the cenet bootloader. or even have hpc2k bootloader to launch cenet (the latter looks much harder to achieve!). so i'm still working on this part.

you can even back up your rom, OS and bootloader in case you have an original 900c, so no need to get the legal official upgrade cf card.

even better: if your OS is corrupted to the point where it will not even start up properly, you will still be able to reflash it to get it to work again as long as your bootloader is reasonably intact.

but now i have to mention possible legal issues. if you have the legal upgrade you bought for your 900, i do not know if you can legally flash hpc2000 back. still, technically you CAN do it if you want / need to. and that's a great thing.

and now the credits. the whole thing was originally bsaunder's idea, then i pushed it further, did a lot of hacking around with the bootloaders and images, but finally bsaunder was able to cut it short by simply taking the risk of flashing a non official bootloader. so he's proved we can go back and forth between hpc2k and cenet.
so basically this is bsaunder's idea.
also thanks to insurgent, then dack who's given us an important hint about the bootloader, and last but not least isotherm who wrote a dump to BIN converter, and for other ideas.

Come on Monica. You know you did quite a bit of the work yourself too.

The best way to go about such an endeavor would be to back up your own HPC2000 OS before you upgrade and save the backup, and then restore it later if you wanted to. Easy to use tools to make that backup will be forthcoming.

Congratulations to the both of you.. You both should be commended...

Monica had this passion to see this through...
I was annoyed that I had to send my mp900 back when I corrupted the OS. (even though NEC was nice and professional about fixing it).

What this means current:
- if you have a serial cable
- you can make a backup of your HPC 2000 OS
- you can then reflash that if you corrupt or upgrade

THIS IS DANGEROUS. If you wipe the device it'll cost at least $40+shipping and up to a month for NEC to fix it.

Monica is working on a way to do this without a serial cable. I hope we can post this method as a FAQ or HOWTO so that everyone can make a backup.

Thanks again for getting this to work Monica!
(and all the others she credited. It was a group effort!)

ps- OpenEmbedded Linux is my goal

yeah we're polishing that serial cable method right now.

three possibilities exist (at least one of them should work, right? )

- get the official updater program to flash hpc2k bootloader / OS - seems pretty easy but we need to test it. (no good if you do not have the cenet upgrade when trying to recover a corrupted OS. it can be used only illegally then.)
- find another way (i.e. secret keypresses) to get into the bootloader - cannot figure it out yet but there seems to be such a possibility. so we will find it
- get the cenet bootloader to load hpc2k. (this one is no good if you have a corrupted not booting OS and hpc2k as bootloader. harder to get that one to load cenet)

and as for the method being dangerous: perfectly safe if you do not flash the bootloader, only the OS. i've flashed in many non working OS'es and could reflash to working OS fine and bootloader update takes only a few seconds iirc. so the risk is not big... but it is there.

we will soon publish backup tool and dumptoBIN converter and instructions and whatnot somewhere.

...and then once linux? would be cool to have that running from ROM - no apm problems etc

Edited by cmonex 2006-09-22 6:47 AM

update:

cenet bootloader is now able to load hpc2k OS. if you have cenet you don't have to reflash bootloader to load hpc2000.

hpc2k bootloader has only about 50% (just a random estimate) chance to load cenet OS and only with very complicated code modifications.

(sure was hard to figure out how to load it... and i can't believe i managed it!)

now it thinks it has a strange version of bootloader i guess it is because it tries to read that value directly from the bootloader code... which is .. well, different.

screenshot shows it

Edited by cmonex 2006-09-23 10:42 AM

another attachment... firmware info with original hpc2k OS... before it was upgraded a long time ago to cenet. so see the difference it definitely reads the values directly off the bootloader code

After copious ARM disassembly and organized keyboard smashing via binary search, cmonex and I have determined that CE.NET bootloader will enter update mode (no serial cable required) if you remove all power sources and then hold (fittingly enough) both C & F down while reinserting battery or plugging in. It then updates XIP.BIN and/or SABOOT.NB0 from the inserted CF card. For the interested, holding down R & F while reinserting battery loads a RAM OS (don't know how to take advantage of this yet).

NOTE: Only the CE.NET bootloader does this, so no help for those with bricked 900's with HPC2000.

Edited by isotherm 2006-09-26 6:57 AM

i should've just held down all the keys after i found out the 900 already checks for the update conditions before pressing power on button (note: no need to separately press power button, it will power on automatically if you're holding the right keys)

anyway next step is load a RAM OS

Edited by cmonex 2006-09-26 7:42 AM

Those wishing to back up their HPC2000 OS before upgrading to CE.NET may find a utility and instructions for doing so here: http://kirk.modevia.com/.ceerom/ceerom.zip

Blimey, well done folks
Top hacking in the old skool sense of the word - I'm very impressed
(I now just wish the sig3 could be flashed - damn those roms!)

yeah, i checked out sig3 and it is true, it cannot be flashed i hoped it could.. nope. would have been next project after 900c

i want to comment on that (now lost) screenshot where i showed how the bootloader version is displayed incorrectly

this recreated and patched cpl fixes it - only if you have some ce.net bootloader but that's natural anyway

Edited by cmonex 2007-07-26 1:05 PM




Attachments
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FirmwCpl_readhybridbootl.zip (3KB - 10 downloads)