Hi,
 
I also tested IS25WP064 successfully (Read and write).
 
I added:
to flashchips.h:
#define ISSI_IS25WP064          0x7017
 
to flashchips.c:
{
                .vendor         = "ISSI",
                .name           = "IS25WP064",
                .bustype        = BUS_SPI,
                .manufacture_id = ISSI_ID_SPI,
                .model_id       = ISSI_IS25WP064,
                .total_size     = 8192,
                .page_size      = 256,
                /* OTP: 1024B total; read 0x48; write 0x42 */
                .feature_bits   = FEATURE_WRSR_WREN | FEATURE_OTP,
                .tested         = TEST_OK_PREW,
                .probe          = probe_spi_rdid,
                .probe_timing   = TIMING_ZERO,
                .block_erasers  =
                {
                        {
                                .eraseblocks = { {4 * 1024, 2048} },
                                .block_erase = spi_block_erase_20,
                        }, {
                                .eraseblocks = { {4 * 1024, 2048} },
                                .block_erase = spi_block_erase_d7,
                        }, {
                                .eraseblocks = { {32 * 1024, 256} },
                                .block_erase = spi_block_erase_52,
                        }, {
                                .eraseblocks = { {64 * 1024, 128} },
                                .block_erase = spi_block_erase_d8,
                        }, {
                                .eraseblocks = { {8 * 1024 * 1024, 1} },
                                .block_erase = spi_block_erase_60,
                        }, {
                                .eraseblocks = { {8 * 1024 * 1024, 1} },
                                .block_erase = spi_block_erase_c7,
                        }
                },
                .unlock         = spi_disable_blockprotect,
                .write          = spi_chip_write_256,
                .read           = spi_chip_read,
                .voltage        = {1650, 1950},
    },
 
 
 
The console output looks this:
 
user@user-VirtualBox:~/Downloads/flashrom-1.0$ sudo flashrom -p ft2232_spi:type=2232H,port=A,divisor=6 -f -w /home/user/Downloads/flashrom-1.0/Flashinhalte/file_8k.bin
flashrom v1.0 on Linux 4.15.0-33-generic (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 ISSI flash chip "IS25WP064" (8192 kB, SPI) on ft2232_spi.
Reading old flash chip contents... done.
Erasing and writing flash chip... Erase/write done.
Verifying flash... VERIFIED.
 
Regards,
Simon