flashrom with buspirate and MX25L4005(A/C)/MX25L4006E flash chip

Hey there,

I am basically trying to follow the steps found on [1] in order to
change the name of my bluetooth receiver BK8000L. I was expecting this
to be easier, but I thought I might learn something here.

I have desoldered the flash chip which is a FT25H04, see [2] for a
datasheet. I was able to dump the flash content to a file called
BK8000L_backup.flash. I have then searched and modified the string
"BK8000L" to "myname", stored the modified flash-file in a file
BK8000L_mod.flash and tried to flash it back to the chip.

The output however is:

# flashrom -p buspirate_spi:dev=/dev/buspirate,spispeed=1M -w
BK8000L_mod.flash
flashrom v1.2 on Linux 5.6.12-arch1-1 (x86_64)
flashrom is free software, get the source code at https://flashrom.org

Using clock_gettime for delay loops (clk_id: 1, resolution: 1ns).
Found Macronix flash chip "MX25L4005(A/C)/MX25L4006E" (512 kB, SPI) on
buspirate_spi.
Reading old flash chip contents... done.
Erasing and writing flash chip... Erase/write done.
Verifying flash... FAILED at 0x0000a000! Expected=0x81, Found=0x82,
failed byte count from 0x00000000-0x0007
Your flash chip is in an unknown state.
Please report this on IRC at chat.freenode.net (channel #flashrom) or
mail [e-mail], thanks!

I have then tried to flash BK8000L_backup.flash but got the following:

# flashrom -p buspirate_spi:dev=/dev/buspirate,spispeed=1M -w
MX25L4006E_bu.eeprom
flashrom v1.2 on Linux 5.6.12-arch1-1 (x86_64)
flashrom is free software, get the source code at https://flashrom.org

Using clock_gettime for delay loops (clk_id: 1, resolution: 1ns).
Found Macronix flash chip "MX25L4005(A/C)/MX25L4006E" (512 kB, SPI) on
buspirate_spi.
Reading old flash chip contents... done.
Erasing and writing flash chip... Erase/write done.
Verifying flash... FAILED at 0x0001a800! Expected=0xd1, Found=0xd0,
failed byte count from 0x00000000-0x0007
Your flash chip is in an unknown state.
Please report this on IRC at chat.freenode.net (channel #flashrom) or
mail [e-mail], thanks!

I hope you can help me with this.

Cheers,
Klemens

[1] https://kovo-blog.blogspot.com/2017/11/bk8000l-change-name.html
[2]
http://pro0fc108.hkpic1.websiteonline.cn/upload/XTX_FMD_NOR_FT25H04_Rev1.pdf