how to load a RAM OS - or boot off a CF card!


DISCLAIMER: NOT RESPONSIBLE FOR ANY PROBLEMS. however, i'm willing to help if i can.



introduction.

this is an advanced way of loading an image onto the 900c!
without a serial cable, it works only with bootloader versions higher than 4.5.1. this means version 4.5.1-6 and 4.10.
with a serial cable, you can use it with older cenet or any hpc2000 bootloader too.
version 4.5.1-6 cannot use this method due to CF reading bug.


more information 1.

new: found out how to convert an ordinary OS image to RAM OS. some RAM OS images that i made are available at my official 900c rom downloads page.


more information 2.

for the newer bootloaders, what you need is just a CF card, nothing else. for the older ones you need a serial cable too, to initialize the process.
the file name to load is XIP.BIN for a 900c and NK.BIN for a 900. 
might be NK.ZIP or NK.GZ (for both 900/900c). but i could not get it to uncompress these properly. XIP.BIN is the normal flashable format.
this method does NOT flash anything, just loads the image into ram and executes it.
you can load kernel or any other code if it is suitable for the environment (hardware initialization etc.).
the addresses in the BIN headers have to be RAM addresses. so no loading of an ordinary OS image that way. it has to be a RAM OS.
the addresses should also be higher in RAM than the bootloader itself - i.e. can be 0x900E0000 or higher.
if you load a ce.net kernel image (useful for testing without having to flash), the kernel will stay in RAM properly after a soft reset too, that's comfortable.
you can also load the updater bootloader for example but only if you patch it first!
update: sadly it isn't suitable for saving bricks with 4.5.1-6 bootloader. still, i'll leave the info here: then you simply need to load a modified updater bootloader while having a properly named OS image file on the CF card (cannot be named XIP.BIN - hence the modification to the updater bootloader).

here is the updater bootloader image for this purpose: http://hpcmonex.net/nec900/files/specupdaterbootl.zip
note: the OS image to be placed on CF card for flashing by this bootloader has to be named XIR.BIN (not XIP.BIN).


instructions without a serial cable:

first steps are similar to the C+F keys method. but you use R+F keys instead!! (R as RAM)

1. format (fully) a CF card that is at least 64 MB. use FAT16 (xp just calls that FAT)! 
2. copy XIP.BIN to card. this is the image you want to load and boot with.
3. insert the card in the 900c.
4. hard reset 900c by removing all power (main battery, backup battery, ac adapter) 
5. before reinserting main battery (do not touch backup battery yet!) or ac adapter (easier), press and hold R and F keys on the 900c. 
6. make sure the battery lock is locked.
7. give power to the 900c while still holding the keys until the 900c switchs on - on its own! no need to press the power key. 
8. if it doesn't switch on within 5 secs, release the keys and it will turn on then (again on its own). 
9. it should tell you that it is searching for a RAM OS / CE image. if the image is compressed it will attempt to uncompress it. if it is a XIP.BIN, it will simply copy that to RAM and jump to it.
10. it should attempt to boot the image automatically. from then on you can do anything.



instructions with a serial cable:

steps are similar to the serial flashing.

1. copy XIP.BIN or NK.BIN (or NK.ZIP/GZ) to a CF card formatted to FAT16. insert that card in the 900/900c.
2. make sure the COM port you're going to use is disabled in activesync etc.
3. run your terminal program (hyperterminal is built in in XP)
4. select 115kbps and software xon/xoff flow control. no parity, 8 bits and stop bits 1.
5. connect your 900/900c with the serial cable
6. to test, turn your 900/900c on (or if it was on, then off and on again!) (as long as you have a bootable OS)
you should get 1 line on your terminal, the bootloader announcing itself as bsquare bootloader for MP900 or similar.
7. hard reset your 900/900c. watch the terminal while it is booting. when it tells you to press ESC, do so, be quick.
8. the bootmenu comes up. you won't see anything referring to the RAM OS load, it is in a hidden menu:
9. simply type 93. and press enter. then the rest is the same as from step 9 without a serial cable.