hallo i just bought a refurbished laptop and the tag says L755-15r. It worked fine for a few days but when i try to do a bios update downloaded from the official toshiba site, it stucks and i force to unplugged it. Now it doesn't open but the fan starts for a few sec and the lights are on. i open it and saw that while in toshiba site the specs has it with intel i5-2410m, this laptop has intel pentium b960 processor, maybe the previous owner change it. My motherboard is DA0BLBMB6F0 i found the bios chip WINBOND 25X40BVSIG 1039 and i try to flash the bios witn eeprom using ch341a. i even bought a new bios chip in case that is broken. i found a few bios bins in some sites but when i try them it says in each file i try the file is bigger. the files are 4mb (4.194.304 kb) as the bios chip or it says chip with contents are in disagreement ???? when i try to detect the chip with the ch341a and ASProgrammer it doesnt detect the chips it say manufacturer unown $$$$$ etc., but both old and the new chip it reads them. any help please???

could you take a look,if this is yours? L755-15R support part number PSK1WE-027009EN Bios v3.60 dated 15/03/2013

Download the original the bios,add your current cpu’s microcode or its updated version if it already exists (which i doubt,maybe previous owner already were using a modded one) into it then flash it
writing a mail to support or finding supported cpus list might be a good idea here

[Guide] Using CH341A-based programmer to flash SPI EEPROM

@leontzam Did you make a backup of the bios chip before writing to it?

no i didn't make a copy unfortunatelly, i was trying to update the bios from ver 1.4 to 3.6 downloaded from the toshiba official site by windows but it stuck and i force to unpluged it and now it wont start

yes that is the model TOSHIBA SATELLITE L755-15R PART NO. PSK1WE-0270093N SERIAL NO. 4B047315W. At site it has it with intel i5-2410m but mine has an intel pentiun b960???? that i m planning to upgrade to i7 if i can make it work again hahaha. When i was trying to update the bios i download the exact bios for the exact serial no that my laptop has and it seemed to be correct but in the progress of updating it came up with an error and stuck for an hour didnt do anything so i unpluged it to shut down. i delete/clear the bios with eeprom /clip/ ch341 and now i must find the exact 4mb bios bin to write it. i download the exe file from toshiba site bios ver 3.60 unzip it and took the fd file to write the chip with ch341 but the size is 4,6mb. I try to write it anyway to see what happens but while the programm says it will cut the the end of file to fit in when i click ok - programm, it say file not in agreemt with chip

Bios image starts at 80000h, first lines are

FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF
5A A5 F0 0F 03 00 04 02 06 02 10 12 20 01 21 00
25 00 00 00 FF FF FF FF FF FF FF FF FF FF FF FF
23 00 30 09 00 00 00 00 00 00 00 00 FF FF FF FF

(if this is correct bios file https://content.us.dynabook.com/content/...ds/sk1wv360.exe did just a quick lock)

i download the file you send me and i use hdx to open the fd file delete from 080000h and above and save it. the size is 4mb 4.194.305kb. when i try to use it from programming with both ch431 and asprogrammer it says file bigger. in ch341 when i try to verify it also sayw not in agreement

Interesting. If I do as described the file is exactly 4.194.304 bytes?

yes i delete all the lines from 08000h and above and save it. in 080000h line the number you say are all correct
FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF FF
5A A5 F0 0F 03 00 04 02 06 02 10 12 20 01 21 00
25 00 00 00 FF FF FF FF FF FF FF FF FF FF FF FF
23 00 30 09 00 00 00 00 00 00 00 00 FF FF FF FF

the size from original 4,5mb has drop to 4mb (4.194.305 bytes) / size in disk 4mb (4.198.400 byte)

and when i try to verify it says chip with contents are in disagreement

the chip is winbond 25x40bvsig and i bought another one new in case the old is damaged but in both chips do the same larger file/disagreement

Well, 4 MB are 4.194.304 bytes. The file is 480000h, you take away 80 000h, remains from 80 000 to 47F FFF which is 400 000h = 4 MByte. And as I wrote I didn't check thoroughly if this is the right file for your laptop.

But: 25x40BVSIG is a 4 Mbit (512kB) chip, and definitely not the bios! It may be EC firmware, keyboard controller, whatever. But it probably was perfectly fine before you did try to overwrite it.
https://cdn.datasheetspdf.com/pdf-down/2...0BV-Winbond.pdf

Always read the datasheet of the chips you try to flash.
Always backup the content of the chip you intend to flash.
Don't flash or erase chips you don't know what they are.

Ok thanks a lot I will look at them, I saw some forums/videos and they say that this is the bios chip but maybe I mixed-up, thanks

Make sharp high resolution pictures of the board, both sides and post them.

in 1 photo i have marked wit red arrow the chip i think is the bios. i saw it in some pictures/videos on internet

Please make a sharp picture of the chips marked or write the precise type for both.

thanks a lot, i founded it and solved it, it works
thanks for the advises