Author Topic: Questions about Sega CD BIOS and Everdrive X5  (Read 659 times)

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Offline ThunderForce

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Questions about Sega CD BIOS and Everdrive X5
« on: July 13, 2018, 06:54 PM »
Hello

I have an Everdrive X5, I'm waiting for the micro sd to arrive (a Kingston 8GB, is it good? I see it's the most recommended here) to finally start.
I have some questions about the configuration and features for the Sega CD:

1-I have an European Mega CD and I want to use USA and JP Bios to play other region games, can I use official Bios files from Sega or do I have to use custom region free ones?
2-Probably silly question, but changing Bios will overwrite the original one or it will remain just on the Everdrive cart?
3-Changing Bios will erase the Save files inside the internal Mega CD memory?
4-Is there a guide to configure folders etc.?

Thanks in advance

Offline Assman

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Re: Questions about Sega CD BIOS and Everdrive X5
« Reply #1 on: July 14, 2018, 09:45 AM »
1. Either way works.
2. The BIOS is loaded like a game ROM; it doesn't overwrite anything in the console.
3. No.
4. According to this, just create a "MEGA" folder at the root of the drive and put the OS and firmware files in it (ignore the OS link in the PDF; it's outdated). The "SAVE" folder also goes there as well as a couple of others, but I think the OS will create them for you (if not, just go back to the manual).

Offline ThunderForce

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Re: Questions about Sega CD BIOS and Everdrive X5
« Reply #2 on: July 17, 2018, 12:43 PM »
Thank you ery much for all the infos.

SD finally arrived, so I'll try to set up everdrive, hope everithing goes well.

Offline ThunderForce

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Re: Questions about Sega CD BIOS and Everdrive X5
« Reply #3 on: July 18, 2018, 06:03 PM »
Everything works fine, very nice.

I have two more question about Sega CD functions:

1-Is it possible to have the Everdrive inserted and to start the Mega CD without loading any BIOS file (and so loading the original Bios)?

2-Inside the Sega CD Bios, when I transfer my saves from internal Mega CD memory to Ram Cart (everdrive), those files are stored in a flash memory powered by a battery inside the cart, or they are saved inside the SD?

I ask this because when I transfered my saves I noticed that the SAVES directory on the SD was empty.

Offline Assman

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Re: Questions about Sega CD BIOS and Everdrive X5
« Reply #4 on: July 19, 2018, 12:29 AM »
1. Yes; if you open the menu (C), you should see a "run CD" option, or something to that effect.
2. I can only look at my Mega ED V1 for guidance, but it backs up the RAM cart data as "RAM_CART.SRM" on the drive root (not in the save folder).

Offline ThunderForce

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Re: Questions about Sega CD BIOS and Everdrive X5
« Reply #5 on: July 22, 2018, 11:18 PM »
Thanks again for the answers.
Finally tried running the original Bios with the option "run bios", after turning off the console, everdrive has created two files:

MEGA/CDBIOS.BIN (this one seems a copy of the original Bios as I can execute it like any other roms/bios files and it's exactly the factory Bios)

MEGA/SAVES/CDBIOS.BRM

Now I don't understand two things: first, on the manual it mention an "SRAM backup" option:

Quote
• SRAM backup: This function allow automatic backup of SRAM save data to SD card. Every
time when user changes the game, the OS will make write a file in MEGA/SAVE/ folder, the file
name will match to ROM name, the SRAM data will be saved to this file. Next time, when the user
selects the same game again, the OS will copy SRAM data from that file to SRAM memory. SRAM
Save works only for games that have battery save functions. The OS will not create the save file if
the game does not use the SRAM memory. If this option is disabled, the OS will not save/load
SRAM memory to the SD file automatically every time when user change the game, but games are
still allowed to use SRAM.

This option seems missing from mega everdrive X5, and I'd like tu turn it off but I don't know how.


The second thing are these options:

Quote
• Cancel: Close file menu
• Copy File to SRAM: Copy file from SD to SRAM
• Copy SRAM to file: Copy from SRAM to file in SD
• Hex view: View file in HEX

unless the everdrive has an internal battery (SRAM) like some Mega Drive carts.

Offline Marteicos

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Re: Questions about Sega CD BIOS and Everdrive X5
« Reply #6 on: July 23, 2018, 03:07 PM »
I guess that the sram backup option was meant for older Everdrive and maybe Mega Everdrive v1, feel free to correct me if wrong.

Mega Everdrive x3, x5 and x7/v2 will always restore/backup sram when applicable. There is no way to disable it on this OS (and no point to do it too).

The copy file do sram is mainly used to bring a save progress from other cart or emulator and the copy sram to file is used to force a sram backup from last game loaded (it needs to be a sram capable game).


Offline Assman

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Re: Questions about Sega CD BIOS and Everdrive X5
« Reply #7 on: July 23, 2018, 11:05 PM »
That manual is a bit outdated, so I'm not surprised it shows options you don't have. It seems to be for the Mega ED V2 (which was eventually rebranded as the X7), but also has references to the older ED V3, which was discontinued before "Mega ED" became the default name for all Genesis/MD carts.