通过上面的分析，发现，其实gzrom-dtb.bin其实有很多空白区域，而且空白区域填充的都是0，这对flash来说并不友好，能否把填充的位置改为ff呢，这样编程的速度也会加快，对flash来说也是一种保护呢。

说干就干：

python脚本改好了：（可能有bug）

"""
python pmonenv.py -f gzrom.bin -o 0x70000 -s 512 al=/dev/mtd0 append="'root=/dev/mtdblock0'"
python ../tools/pmonenv.py -f gzrom-dtb.bin -d ls2k.dtb -w  al=/dev/ram@p0x110000000 al1=/dev/ram@p0x110000000 append="'console=ttyS0,115200 initcall_debug=1 loglevel=20 nosmp'" FR=1
"""
import struct
import sys
import getopt
import os

def readenv(fname,foff,fsz,argv):
	f=open(fname,'rb+')  
	f.seek(foff,0) 
	a=f.read(fsz) 
	# print("1 a read = ",a)   # 1
	# print("a.len = ",len(a))   # 2 
	a=a.ljust(fsz,b'\x00')    
	f.close()   
	d={}
	b = struct.unpack('!'+str(len(a)//2)+'H',a)  
	# print("3 b = ",b)  # 3
	# print("b.len = ",len(b))   # 4
	if(sum(b)&0xffff):  
		print('checksum error, rebuild env')
		t = argv
	else:
		e = a[2:].find(b'\x00\x00')  
		# print("4 e = ",e)    # 5
		t = a[2:2+e].split(b'\x00')+list(map(lambda x:x.encode('utf8'),argv))   
		# print("5 t = ",t)   # 6
	# print("\n for start*******************")
	for i in t:
		a=i.split(b'=',1)  
		# print("6 a = ",a)   # 7
		if len(a) > 1:     
			d[a[0]] = a[1]   
		elif a[0] in d:   
			del d[a[0]]
	# print("for end*******************\n")
	return d

def writeenv(fname,foff,fsz,d):
	# print("\nwriteenv start*******************")
	# print("7 d = ",d)   # 8
	a=b'\x00\x00'   
	for i in d.keys():   
		a += i+b'='+d[i]+b'\x00' 
		# print("8 a = ",a)   # 9
	a=a.ljust(fsz,b'\xff')    # full ff
	b = struct.pack('!H',(-sum(struct.unpack('!'+str(len(a)//2)+'H',a)))&0xffff)
	# print("9 b = ",b)   # 10
	a=b+a[2:]
	# print("10 a = ",a)   # 11
	f=open(fname,'rb+')

	size=os.path.getsize(fname)
	print("size=",size)
	c = ""
	c=c.ljust(foff-size-0x4000,'\xff') # full ff
	f.seek(size, 0) # full ff
	f.write(c)

	f.seek(foff,0)
	f.write(a)  
	f.close()

def writehexenv(fname,hexbin):
	f=open(fname,'rb+')
	f.seek(foff+fsz, 0)
	f.write('\xff'*256)
	for b in hexbin.split(','):
		i,v = b.split(':')
		f.seek(foff+int(i,0),0)
		f.write(v.decode('hex'))
	f.close()

def writedtb(fname,dtb,foff):
	# print("\n writedtb start----------------------")
	f=open(dtb,'rb')
	a=f.read();
	# print("a.len= ",len(a))  # 12
	f.close()
	a=a.ljust(0x4000-8,'\xff')
	# print("a = ",a)
	b = struct.pack('I',(-sum(struct.unpack(''+str(len(a)//4)+'I',a)))&0xffffffff)
	a=b+a+b
	# print("a.len= ",len(a))  # 13
	# print("a = ",a)

	f=open(fname,'rb+')
	f.seek(foff-0x4000,0)
	f.write(a)
	f.close()
    
if __name__ == '__main__':
	opt,argv=getopt.getopt(sys.argv[1:],'b:o:s:f:wd:')
	opt=dict(opt)
	foff = int(opt['-o'],0) if '-o' in opt  else 0x000ff000  
	fsz = int(opt['-s'],0) if '-s' in opt else 500  
	fname = opt['-f'] if '-f' in opt else 'gzrom.bin' 
    
	print(foff)
	print(fsz)
	print(fname)

	d=readenv(fname,foff,fsz,argv)
	print(d) 
	if '-w' in opt:  
		writeenv(fname,foff,fsz,d)   
		if '-b' in opt: writehexenv(fname, opt['-b'])
		if '-d' in opt: writedtb(fname, opt['-d'], foff)
           

生成的bin文件中，空白区域为ff了：

更新试试，能否启动？

启动成功！！！填充ff不会影响

但是说实话，感觉烧写的速度并没有明显提高，我没有计时