NAND related kernel panics

I replaced the battery 3 months ago and had no problem at all until very recently. It started to reboot randomly but could work flawlessly for a couple of days. And then suddenly it failed to boot properly. If by chance it reaches the home screen and I enter the unlock code, it freezes, the screen fades or even gets vertical stripes and the device reboots.

I sorted the relevant panic logs and got this (each line is a different panic log):

"FAILURE INFO: bus 0 ce 0 type 0x00000a11, 135696 bytes of additional data at 0x802a9000\n"

"FAILURE INFO: bus 1 ce 8 type 0x00000012, 135696 bytes of additional data at 0x802ee000\n"

"FAILURE INFO: bus 1 ce 8 type 0x00000012, 135696 bytes of additional data at 0x8031d000\n"

"FAILURE INFO: bus 1 ce 8 type 0x00000012, 135696 bytes of additional data at 0x803b0000\n"

"FAILURE INFO: bus 1 ce 8 type 0x00000012, 135696 bytes of additional data at 0x8fbf9000\n"

"FAILURE INFO: bus 1 ce 8 type 0x00000012, 135696 bytes of additional data at 0x8fdb6000\n"

"FAILURE INFO: bus 1 ce 8 type 0x00000012, 135696 bytes of additional data at 0x8fe02000\n"

"IOP panic: fmiss_yield: WMR_PANIC: "Sequencer Timeout!" drivers/apple/h2fmi/fmiss_ppn.c:431 "

"IOP panic: h2fmi_get_nand_status: WMR_PANIC: "Timeout waiting for NAND status: 0x00\n" drivers/apple/h2fmi/H2fmi_ppn.c:1910 "

"IOP panic: h2fmi_ppn_set_channel_power_state: WMR_ASSERT failed:(result == FIL_SUCCESS) drivers/apple/h2fmi/H2fmi_ppn.c:2241 "

"LBA mismatch in GC; lba: 1158140, meta 1157628"

"Unable to allocate 1663243088 byte PPN buffer (bus 0 ce 0 geb type 0x0000fc35)"

"WMR_ASSERT failed:(replacement_count <= 1) /SourceCache/IOFlashStorage/IOFlashStorage-716.10.5/WhimoryPPN/Core/SVFL/s_vfl.c:2120"

"sftl: lba mismatch; lba:0x12ee2, meta:0x6744d\n"

"sftl: lba mismatch; lba:0x1cceb6, meta:0x1cceb4\n"

"sftl: lba mismatch; lba:0x25d8, meta:0x9a63bcd3\n"

"sftl: lba mismatch; lba:0x2f753b, meta:0xc534d\n"

"sftl: lba mismatch; lba:0x44a49, meta:0xdc611\n"

"sftl: lba mismatch; lba:0x55b92, meta:0x55990\n"

"sftl: lba mismatch; lba:0x74ed7, meta:0x2074ed7\n"

"sftl: lba mismatch; lba:0x8f6c, meta:0x8d6c\n"

They all seem to refer to NAND errors. I tried to disconnect the proximity sensor ribbon as suggested by another post but the device still cannot boot properly.

Any idea what's going on?