I tried to program SPI Flash NVRAM (S25FL064A) from U-boot, but it not allow to write:tftp 0x80000100 nvram.bincp.b 0x80000100 0x007b0000 0x00050000There is no error shown after cp.b command, just not allow to write. What can be the problem?Flash memory structure, from U-Boot 1.2.0 printenv:Serial Flash [Bus:0 CS:0] : s25fl064a 8192KB, 128 sectors each  64KB7 cmdlinepart partitions found on MTD device spansionpartitions[0] = {.name = U-Boot, .offset = 0x00000000,.size = 0x00020000 (128K) }partitions[1] = {.name = env1, .offset = 0x00020000,.size = 0x00010000 (64K) }partitions[2] = {.name = env2, .offset = 0x00030000,.size = 0x00010000 (64K) }partitions[3] = {.name = firmware_EH, .offset = 0x004a0000,.size = 0x002d0000 (2880K) }partitions[4] = {.name = nvram, .offset = 0x007b0000,.size = 0x00050000 (320K) }partitions[5] = {.name = UBFI1, .offset = 0x00040000,.size = 0x003b0000 (3776K) }partitions[6] = {.name = UBFI2, .offset = 0x003f0000,.size = 0x003b0000 (3776K) }Creating 7 MTD partitions on spansion:0x00000000-0x00020000 : U-Boot0x00020000-0x00030000 : env10x00030000-0x00040000 : env20x004a0000-0x00770000 : firmware_EH0x007b0000-0x00800000 : nvram0x00040000-0x003f0000 : UBFI10x003f0000-0x007a0000 : UBFI2
Flashing NVRAM with U-Boot 1.2.0
linux;firmware;memory;serial communication;spi